The main issue on Console will be people using Alt accounts to open the door from within the bunker, also even on PC players will log inside & when logging back in for the next play session will abuse the internal switch to let there friends in, basically cheesing the need for a Punch card.
A simple solution to this issue could be an extension on the server hopping mechanic, ie if a player logs inside the Bunker, when logging back in they are returned to the surface. I am aware this could be abused for a quick exit from the bunker when trapped in the water puzzle, but maybe that level could be not included in this process