To me Tav looking horrified in the kiss makes perfect sense. Not for ever Tav, but even for evil ones I can see it timing perfectly. It just represents a Tav that fell for the most classic of evil flaws; hubris. They believed they would be his equal, they would be special, they would be the exception, safe from his manipulations and abuse. All of the benefits, none of the consequences. Then they realize they were wrong, they were outplayed, and it's too late to turn back.
This is just one of the problems with role-playing in his game. The cinematic nature and necessity of expressions means players are never going to be able to rely on the game letting them give their Tav the nuances they should have, and so their roleplay is limited even more than in other games of this genre.
