Overbook the session with like 5 players so even if 2 are missing, they're still 3.
Accept that character may disappear, sometimes you'll find role-play reason Being stuck with paperwork, family, duty sometimes you don't (But there is a kind of acceptance in not challenging why suddenly a PC disappeared in the middle of a dungeon when they're player isn't here)
You had your local version of Notre Dame fire.
Just hope everyone was OK in the end