Is there any backup plan for worst case scenarios regarding the upcoming merge?

So as I am not too savvy I was wondering if there's any kind of backup plan for the upcoming merge, just for the case if the unimaginable happens like a malfunction or huge exploit or something else bad, no one could've thought of … Would a rollback be the only viable option? (Btw I never cared much about the DAO rollback and I would not care again as it was the community's majority which decided to go for it)