He still came within seconds of death immediately after being in a coma and it's been only a few hours. The coma in question was a result of procedures he did months ago. Something this serious, he shouldn't even be standing around, never mind even considering going outside.

If the teleporter can't work with the shield activated, it should be established in-story. If it can be, there's no reason they can't send Ravage out again to locate the ships while the Decepticons are busy. Sabotage one, see what kind of resistance, if any, they're looking at from the other. Get a few people over to take it, if necessary, just get everyone on board if not. The Maximus armor isn't necessary if there's not a direct fight, but if Minimus really insist on taking it along, they can just swing back for him. It'd still be way less risky than less than twenty people, some of them non-fighters, running headlong into a fight against hundreds of soldiers. Which is a ridiculous plan plus or minus the ability to steal an escape vehicle, frankly.

(Sorry for lack of quoting in this response, I'm on my phone.)