At the end of a mission:
- I called & entered the Elevator before my wife;
- My wife called the elevator before I could exit (the doors opened for me then closed);
- I was returned to the top & I saw my wife's character enter (she didn't see my character, however);
- The elevator opened for my wife and she was able to exit. For me, however, the doors remained closed.
Simple work-around: I fast traveled to her location.