You can just create a game while in town, then leave the game.
I normally create a game before starting a catacomb, this way I can just leave the game and re-create game. This is easier than logging out and logging back in. (Well that is my opinion anyway).
There is always the trick to reduce all spawns down to low hit points, also note to kill any of the healers first... then try to kill them fast from there.
Hope this helps.