The broken watch is a comfort, it helps Rick with his life. Not so much for Hershel, Dr. S. is about to die. Trying to help the living and carrying the dead outside; Sasha, Glenn and Hershel end up doing the exact same thing as Carol before the end of the night. A fact Rick is confronted with, when he confesses Hershel he left Carol behind.
It takes just one so all hell would break loose, Rick can't handle the fence any more than Maggie help her father to handle the mayhem, many die simply because the victims of the flu raise to prey on the dying. If Tyreese's group wouldn't have got there in time, they would've perished either by the walkers on the fence or the ones from the inside.
Either by the dead preying on them or the Governor coming back to hunt the living