Your coach should have come with two slide locks to keep that from happening if the hydraulics fail.
Ours came in crooked a couple years ago and I ended up replacing all the hoses and having the synchronizing cylinder and front and rear rams rebuilt. I also relocated the sync cylinder to a more accessible location in the basement overhead. Luckily, the slide didn't get stuck, it just jammed up the inside facia trim around the slide box. While I was reading all the literature about replacing the hoses and rams, I found a short blurb that said you shouldn't reverse the direction of travel without fully extending or retracting the slide. I never knew that.