+1
This quest is quite a mess, gameplay-wise.

Originally Posted by The_Red_Queen
At the very least, the game should automatically put you in turn based mode when the door opens, in the same way as it does for traps that require time-sensitive action to escape (eg the trapped tomb in the ruins).

Agree. This could help a bit (that and fixing NPCs not moving to their next spot).

Side note : especially when the "Turn based mode" is not the most inviting feature to be triggered manually. Personally, I find that feature a bit rough, mostly because it takes a long while to activate and deactivate.