Open inide door one direction, outside door the other direction (back to back) and move the wrong direction (into the door opening animation) and the player gets stuck in the door. I'm not sure anyone has explained the issue this well. Try to close any door standing in the doorway and the player will get stuck in the door. I haven't raised the issue because I thought it was rare. Even Traitor gate ways.
Blaster or Yoda,