Re: What happens in Vegas...
It sounded to me like the attack on the casino was an unplanned interruption, not whatever the group and Captain Zapper had been in Vegas to deal with. If he was ditching the group on the whole reason they were in town, that's more serious.
Shooting Star would be a little annoyed that he was a no show, but not enough to go looking for him. His personal life is not her problem - she has plenty of those herself. She doesn't really want to know. When they next met up, she'd be "Next time, make sure we have a way of reaching you in case there's a real emergency." It was no big deal - but if it had been a serious matter with better villains or a doomsday device or something, the group still would have no way of reaching him. But she wouldn't be comfortable with harassment of the Captain, because she doesn't want to be held to a 24 hour standard of readiness either.