the seats are always “hot” while you’re airborne and until you safe them. Just pull the handles and you go. If you mean because one guy pulled and it failed they all were in danger of going at any moment if the sequence continued, that’s not how it works.
They were each doing a manual ejection. Pull and you go - only you. Then the next guy and so on. First guy that tried stayed, so they decide to go to plan B rather than leave him to die.