I was unclear there, sorry.
What I meant was, detect evil would have indicated that their target wasn't evil (and hence, as a paragon of goodness and law) that they should at least try reasoning...
Those who go around with magical disguises impersonating people are well advised to arrange alignment/thought shielding/anti-scrying effects. First you capture (if they don't aggressively resist and you care enough to not kill them), then you strip them, then you chain dispel them, then and only then do you try your scrying/interrogating/negotiating (beyond basic surrender). I will say that a paragon of goodness and law who let magical impersonation go uninvestigated without significant mitigating circumstances would get a serious black mark in my books. Those sorts tend to be nasty!
Why was the Inevitable impersonating a specific NPC in the first place, and then a PC? Kicks and giggles?