Kaidan shrugged a shoulder, "Common sense? Once I figured out that anything from our realities can just show up here for a weekend rendezvous, I started planning what to do if anything or anyone from mine ever did. What I'd do if Saren showed up, though a lot of that would depend on whether it was Average Asshole Saren or Indoctrinated And Pregnant With Reapertech Saren. What I'd be able to do if a Reaper showed up, though the main answer to that is mostly 'scream and die' because even one is bad news. Friends, enemies, monsters." He paused a breath, and shrugged again, "Habit."