How to fix survivors suiciding on first hook
Simply take away the option to unhook yourself unless you're running a perk like Deliverance or others that would give a chance to escape, or the camping meter fills up. You could even re-enable the ability during endgame. Problem solved.
Comments
It would be a little "balancing with axe" situation.
I would give them the same amount of penalty as DCing. For starting. Also you should prevent unhooking themself for example the first x minutes, or if not another survivor on hook within x minutes or something. Completly remove the self unhook without perks would destroy many offerings, perks and such. Even tho I hate when a survivor get lucky and get out cause of it.