Something Something-If your friends jump off a cliff, are you going to?
Basically that. If my friends decide to make a sacrifice, that's on them. If I'm an asshole for not choosing to do the same, then they can't really be called my friends if I'm expected to suffer at their choice.
Not that Reiji or Mizuki are assholes, they accept that the risk is theirs and theirs alone and don't drag Suimei down with the consequences of their decisions. They're good friends, do what they believe in without costing their real friends.
But Shrimp Tits can go fuck herself for trying to insert herself into the friend circle.