So I wrote about this in the shoutbox already, but don't want to spam it and maybe creating this thread helps someone else as well.
I followed this tutorial: https://twhl.info/wiki/page/Tutorial%3A_Elevator_Doors_that_move
And the elevator works all fine for a time and then suddenly, the doors get out of sync and the elevator stops moving. At about 2:00 minutes in the video I switch to blood1 from Richman to show that his elevator doesn't bugs out, no matter if you move while pressing the button or not. I think this is the cause for the doors getting out of sync, but I'm not sure(well in the video the elevator works if you don't move). I know that the tutorial uses delays on the path_corners, I removed those and it still didn't change anything(well besides I had to get the doors in sync with the multimanager instead). The elevator from Richman however uses several trigger_relays that get triggered by the path_corners once the doors pass them, as seen here: https://twhl.info/journal/view/8958
But even though I've been taking a look at his elevator setup now for about 2 days, I don't quite get the logic behind it. GoldSrc's way of showing in/outputs, or better the lack of that, isn't helpful as well, in Source that'd be easy as cake.