I'm going to answer, but please know that this isn't the only answer. The moves have triggers that take place in the narrative and how zoomed in and cinematic it is. The fiction decides. That said:

If we remove most fictional cinematics... and assume Dremmer and the PC are in the scene.

A) [PC]Bob vs Dremmer
Bob wants to kill Dremmer, Dremmer is prepared to fight back. The Move: Single Combat

B) [PC]Bob vs Dremmer
Bob wants to kill Dremmer, Dremmer is prepared to run the fuck away. The Move: Seize by Force or Cat and Mouse

How this works varies a lot depending on the complications Dremmer can involve in his escape. Please note that there should be complications unless Dremmer literally has no where to go. First you ask, who has the advantage. If the PC has the upper hand, I'd probably go straight to seize by force, where Dremmer escapes unless the PC either deals 3+ harm after armor or picks to seize definitely Dremmer's escape. 2harm, Dremmer escapes but probably wont be around much longer. 1harm Dremmer is in the wind. Cat and Mouse can follow this if appropriate, but if Bob catches him again, there might not need to be another seize by force to end him.

If Dremmer has the advantage, then Dremmer just Runs. In order to catch him Cat and Mouse happens (with Bob as the Cat). If Bob gets to pick where he catches him, then Dremmer's got no way out and it's Single Combat time. Otherwise if Dremmer gets to pick where, it might be seize by force or it might be something else, depending on where (or who) Dremmer gets to.

C) [PC]Bob vs Dremmer & Gang
Bob wants to kill Dremmer, Dremmer and gang are prepared to fight back. The Move: Single Combat

Single combat doesn't mean one person vs one person, it applies just as easily to one person vs one gang of people.
The PC does not get the option, I just kill Dremmer. They have to fight through bodies to kill him, and those bodies are actively getting in the way / fucking Bob up. Deal harm to the gang, and the leadership will start to crumble, the fiction comes in and asks are these boys ready to die for Dremmer? If so, then fight on, if not, maybe they scatter and now its PC vs Dremmer, refer to scenarios A or B.

D) [PC]Bob vs Dremmer & Gang
Bob wants to kill Dremmer, Dremmer uses his gang to help him escape. The Move: Seize by Force

Bob has to fight his way through to even START chasing after Dremmer. That's seize by force, definite hold is definitely fighting through the gang. Interestingly this is actually the best way for Dremmer to survive and tends to deal less damage to his gang, because the PC's focus is getting past them not kill all of them to take Dremmer down too. Still: Dremmer Runs. Bob has to fight through the gang, the gang will break if enough harm is dealt... but they might break in the same direction the PC wants to go, thus, to keep them out of the way, seizing a way through is essential. Followup, Cat and Mouse (see scenario B), unless the PC didnt make it through with one move, in that case, Dremmer's gone.


E) [PC]Bob vs Dremmer & Gang
Bob just wants to kill Dremmer, Dremmer fights or runs. The Move: Seize by Force under Fire
Seize Dremmer's escape (running), or seize a way through (fighting) the gang to Dremmer, while acting under fire of all the people trying to stop Bob. Re: old post. I would probably play scenario C and D more often then not. This is AW, people in the way of killing, probably get killed. If the gang is ready and staring you down, you're probably not going to assassinate the guy out of the middle of them without serious Cool rolls. And even if you do, you have to Cool/Hard you way back out too. Note: I, after thinking it over, REALLY dislike this option.

PS
The thing to note here is that if there are no other complications in the field, no people getting in the way, positioning or tactical shit that matters, and the killing needs a roll, it's probably single combat. If they cannot run, they will fight, and a cornered person fights much harder then one who can run. Same goes for a gang. If they're trapped, they will fight until they're all dead.  If Bob is attacking a gang of people, Dremmer can use that gang's health pool to stay alive all the way until it either cracks under pressure or is crushed. 5(maybe4) harm to the gang is when I'd deal 1-harm to the Dremmer. 6(maybe5) harm to the gang, Dremmer's dying in there too. 6+ Dremmer's been dead.

This actually makes the battle babe even cooler. Visions of Death: Dremmer Dies. Battlebabe hits the gang with one exchange of harm (preferably from go aggro, but seize by force too) and chooses all the get away, suffer less harm, frightens them options. Because, the battle babe already killed Dremmer out from the middle of them (visions of death) and only had to trade harm to make sure the battle happened, so her focus is actually on escaping.

That's my 2-cents.

( I have been, there isn't much to say other then the players love it, and it's only helped in a real way make a 10+ feel like a 10+. )

No. I disagree. This is never okay.

You may use seize by force to seize his escape by force, to prevent him from getting away from you. But the only way to determine whether or not you killed someone is by dealing harm to them. If you're hitting the whole gang, you don't get to pick which one is dead unless you're the battle babe with visions of death.

If you want to hit just one guy, then you can seize the opportunity to make a move just against him. Be warned, his buddies might still be helping, meaning you're exchanging harm against this guy, and the entire gang is exchanging the harm back. If you're going for the surprise attack, Sucker Someone has the details.

If the fiction seems like, sure this guy could reasonably be up front, maybe, I'd let someone seize that guy by force, but that would only ensure that he is one of the gang members that was injured. It is the gang's harm clock that says how many are dead (if any).

If you wanted to skip the first seize and try to act under fire to get to the guy, okay. Lets go step by step. You act under fire as you rush them, pushing through the first guys and jumping into the middle with your target... You hit with a 10+, so no body saw you coming or stopped you, or hurt you on the way. But now you're RIGHT were you asked to be.... in the middle of the gang with guns trying to kill their boss. Okay, now make your seize by force, also under fire of all these guys trying to stop you / kill you. You're acting under fire here not to fight, but to ensure you have the chance to deal that single combat against him. If he's trying to run, then it's sucker someone's version of go aggro instead.

If you hit with the act under fire, no one manages to stop what comes next. You make a seize by force against the boss. You are dealing harm just against him, not the gang. He's exchange back however is probably using the gang as a weapon, so you'll be taking the full brunt of the them. If you hit a partial, maybe you suffer more harm from the gang because you were exposed, or maybe he suffers less harm because the gang tries to protect him, or maybe you can do it, but you'll be way out of position afterwards for a clean escape. On a miss, you get the downsides, except you cannot target just your guy, and now you'll have to fight through them all to get to him, and you better seize his escape by force there.

If you have the chance to just drop in on all of them, then the first act under fire to break the lines and get to him isn't needed. You can just do the seize by force while under fire.

It'll take practice. Don't put to much pressure on yourself to do it "perfectly". Even after years of running these sorts of games, I find myself constantly learning, and messing up. lol. Give yourself some rules of thumb, and just jump in. The only real way to learn this, is to do it.

Well. Forum gaming is more like writing a book then gaming. There's a lot of do this and come back to it later and do it some more. In person, everything is immediate, you say something and you can see the reactions of those around you immediately. Play off that. You do something, and shit goes down hill, but there's no time to think and carefully mule it over, you gotta do something now. Do  the first thing that comes to the characters mind. When you're playing in person, it's best to start figuring out little rules of thumb for a character. ex: He's really aggressive, anytime I'm pushed, my reaction is to push back, even if I shouldn't. He's really aggressive, if I don't know what to do, or get stuck, I'm going to beat or threaten the right answer out of someone. He's really emotional, and doesn't know how to handle other people, so he makes contact in forceful ways.

You can figure out a few go-to rules for your character pretty quick, make sure they involve DOING something. Easy rules make for quick fall backs to decision making, which can help keep the fiction flowing.

Pretty much the only other advise I have is to play with the people around you. That's really the most important part, and the only one that makes or breaks a game.

Stats
You can highlight Hx.

Moves
There has been a pretty sizable update to Battle moves and Seize by Force. Road War Moves were added along with a complete reimagining of vehicles. Subterfuge moves have been added. Some old moves have hold or effects on misses now, many have undergone slight text changes which may have implications on how they're used.

Playbooks
The Operator is gone, Driver underwent a substantial change. Some class moves have been tweaked. Character creation Hx was completely redone. Angel Kits were substantially updated. MaestroD was added as a base class. Prosthetics are detailed for the savvyhead, and small but significant changes can be found in the improvement lists for the playbooks.

Barter/Lifestyle
Barter moves are mostly untouched, but barter functions entirely differently then before. A number of barter is spent to pay for your lifestyle every session, rather then every month.  All classes have a built in moonlighting, but this takes place on screen and in the narrative, not triggered or handled by rolls occurring in between sessions and in downtime. This is a massive change to the tempo of the game, and helps to make scarcity and survival become real things for the player characters.

DM Tools
Many DM tools are the same, all of them are familiar, but there are new tricks and suggested aids that have overtaken old examples. Namely fronts aren't present at all, new threat mapping aid is provided, and a bunch of new threat types have been detailed with some minor updates to the classics. 

Other Stuff
More harm types are detailed.
More weapon types are detailed.
Coming back from 12 harm is done entirely differently.
Some more fun custom moves from play testers are in the back.

If you want the details for the changes, I recommend the 2nd edition book.

There would still be the question of the differences between the 7-9 or a 10+. Maybe only some of these are known to the character on a 7-9, but you still do the whole thing- aligning a stake to the question. This is what will happen, but what will she do without that knowledge? Dunno.

I find the best benefit of the Weird roll is by forming relational questions between the PC and NPCs / World. I'd be worried that this wasn't taking place without making that play a major part of it. Of course, if we held to the object of the maelstrom questioning the character...  you could always ask the character what do they feel about these choices, or who they see as what card. Dunno.