but perhaps someone can remind me...

Why is it that assassins can't vanish in cabals? Other than simply using it as a way to get past the outer?

IIRC, all cabal rooms happen to be flagged in ways that make none of them viable 'landing' rooms for vanish. I mean, you can't teleport into a cabal either.

Huh. Was it an intentional decision to prevent "in-cabal" vanishing, then, was the goal just to stop people bypassing the outer and this happened to be the easiest way to implement it?

...is allowing assassins with home-field advantage to vanish in a cabal. Not intruders.

It makes sense to me that a cabal would be on "red alert" when outsiders enter it...in truth it should have more effects on aggressors, but that's another story.