I suspected you wouldn't be smart enough to figure it out, the number is arbitrary, it's making a point that you don't hit some milestone and then just because whatever you've been doing has worked so far, you will continue to be fine.
If you keep taking unnecessary risks with your health, eventually it's gonna bite you.*
Oh my god, do I have to explain everything? Of course physical death doesn't grant immortality, everybody knows you both have to have your blood drained by a vampire and then drink some of the vampire's blood. You're such hard work.
*That was figurative speech, need me to explain?