Is that the case though? Because the Serial Killer and Mafia could potentially kill each other, right?
Ok here's the rub though, why do they do this, if both are logical players? They don't, kinda only happens if both sides don't know what they're doing.
So now you just have both kills turned on town, or maybe one at best crosses over
Every scenario Luka has outlined is actually better than the alternative of leaving Serial alive, because with serial gone, town can at least control the game's direction. 2v3 is a very winnable game state. We could hypothetically lose after today if he's serial and we don't lynch him