1. Yes, however especially at lower levels you're burning time, END, etc. breaking down the door - at which time you're attacked by the ambush.
2. Depending on the team and how it's been going, you may have *several* ambushes sitting there weaiting for you, and toggles generally won't help.
3 ... especially if this isn't the first trip and you get into a cell with the door already broken. Which means, no, you don't get time to "collect yourself and retoggle."
Which has been mentioned before in this thread.
Know what else can be right there? The ambush. 🙂
Granted, these happen in teams that have quite a few things not go right - and my general way of dealing with it *is* to just solo them, but yes, I've been in this exact situation more than once. I'm not theorycrafting that "this could happen."