I actually found a logical
branch point once that the game failed to account for. That was cause for celebration.
After helping Paul escape from the hotel (he's only dead if you abandon him there----any other outcome he's alive), I got to Battery Park. Anna was already dead (killed on the 747), so Gunther was the only one waiting there. He's invincible at that point, but you *can* get around him if you lure him down into the subway station and then take the back exit out. I did that, wiped out the security bots, and use Microfiber Muscle to push one of the large (normally unmovable) crates out of the way. I got all the way to Jock's helicopter! (The map is extremely undetailed beyond the Gunther confrontation zone, incidentally.) Unfortunately, Jock failed to acknowledge my presence, and I had no choice but to go find Gunther and get myself hauled off to the Secret Base on the point of a flamethrower.
Not a video, but definitely check this out: