this is my first playthrough and i took combat strength now i am at the point where i might be captured i killed agent nevara at the 747 to spare the captured nsf leader and helped my brother escape now i am trying to avoid capture at battery park first is it even possible? did i need the other strength aug? did i need to make different choices? is there any way to kill gunther? lastly if the answer to all those questions is no is there any perk or bonus dialog to killing everyone but gunther at battery park? after the 747 i thought it would be posable since you can stop nevara from killing the prisoner so you can see why i'm confused here

You have to be captured.

Yeah. Whether you die or surrender to Agent Hermann, you'll be sent to the next mission.

Also, there is no special bonus to killing the other troopers in Battery Park. There might be a skill point bonus involved in reaching Battery Park to begin with, though; I forget.

This is actually an extremely lame part of Deus Ex. No matter what you do, the outcome will not change.

The first time I tried it, I could easily have escaped, but there are invisible walls stopping you from leaving the area. Next time I killed everything in my way except Grunty, but he's unkillable, so it doesn't matter.

The whole thing should have been resolved with a cut scene or something.

Yeah Gunther this ugly unkillable bastard... Like UniversalWolf wrote it's a very lame - or better: frustrating - part of the game.
I've wasted perceived hours to find out there's no escaping possible at Battery Park. All troops were killed, all Mechs destroyed or disabled, but then invisible walls and a Gunther who's "eating" all my ammo... poor dead end.