Screw knives! This is Mordheim! (Draws sword and crossbow pistol)
And since it is Mordheim its really what makes sense to your group. Although I'd appreciate it if no one e-mails mine about this discussion, because we had moved on and I hate going back.
Since there is no stand and shoot rule in the Mordheim system and the attack is an always strikes first in hand-to-hand, we play that you have that crossbow pistol in your hand. If the shot was resolved in the movement or shooting phases or if someone had argued strongly that we should just do it like stand and shoot, we might have done differently. We often have a player or 2 who have never played Warhammer, so if we use a crossover rule we have to explain it as well...