The next Leader is supposed to be Erik's second in command, Zonaira. She's been his Second for at least a few years now. This is a militaristic organization, except that their highest member often goes on the life threatening missions. It would be totally illogical for them to have no plan for succession. They would stay underground for at least two weeks after a failure like that, because they still want to "bury their dead" and possibly see if there is any word on where they ended up. But they have to continue, and they can't afford to fight about it each time someone in a high rank is lost.