We decided to skip the 2nd puzzle and when we triggered the trap we got the situation where the door would collapse and we would have to move the rocks out of the way. Everything was going fine, the door was cleaning up, until one of the party members picked the last rock. On their way to the rock pile, the door suddenly became filled with rocks again and the party member couldn't drop the rock in the pile. We tried using the "Defeat me" command and went back, but the door was still blocked and we couldn't interact with it.
Lesson learned, don't skip the puzzles.