Isn't the halc supposed to fire before I disable him? It was a two shot kill which may contribute to it, but still, isn't the trap supposed to trip and prevent the disable?

Nah, it's not a problem. Find a weak or damaged enough ship, and you can kill it before or on the round the halc goes off. Only thing that guarantees other players can't disable you is a calming amp.

Yeah, if their damage cap is big enough and their hull is low enough you can often disable them before the halc goes off.