So here is how I feel the General should escape. However, it does require someone getting injured, but it could shed some interesting light on things.

As of right now, no one should know what these experimental weapons can do. During the attack on the base, the General can use one of the new weapons in a desperation maneuver. What follows is a concentrated blast that will pass through any of the Purist troops, but will connect with a member of the team. Damage I figure can be left up to whoever volunteers to take the bullet, but I imagine it'd be like a microwave gun: severe burns internally, charred armor, etc etc.

Anyway, that's what I'm guessing could lead up to the General escaping.