Ah, of course, that would be a possibility for the detector!
There’s an issue I observed with parallel worlds which I posted a while back: in summary, my simulations misbehaved if the parallel world contained a volume right on top of an identical volume in the physical world. I did not investigate the issue further (I was lazy and added a small displacement…), but it looked as if the parallel navigator was getting confused when two surfaces were crossed at the same instant. If this is the case, that would limit this approach.