In Act I, Mission IV you are able to fall down in the crack/canyon so that you cannot move but you’ll stay alive. Only way to skip this is to leave the game. Pretty frustrating, you should either make the crack unreachable or make it so that there is no flat surfaces where you can get stuck. You can see items left behind by another party member but I couldn’t jump all the way down and got stuck in that corner.
Also as being host I had to disband the party to get out of there so no loot/exp for that failed mission for anyone. Which could be avoided if you could “pass” on the host to another player when the current host has left or disconnected.