This just came up:

Bad Guy is at medium range.

Bad Guy: Draws pistol for his action

Player: I move from medium to close, then do an extra move to engage the man with the pistol and attack him.

Now don't you think the man with the pistol, who sees him coming from a mile away, would have a chance to shoot?

Has anyone come up with a good house rule for this?

Drawing a pistol would probably be a manoeuvre, not an action. Meaning the bad guy can shoot before the PC has even made 1 manoeuvre.

But if he really insisted on holding an action, I thought this was covered in the main RB? In any case, I'd allow the Bad Guy to act and the initiative token he used would be shifted down to the new, lower level.

The bad guy could have fired, but he was waiting to see what the player would do.

There are actions that allow you to act when it is not your turn. Alternatively, you can"house rule" it with the perform a stunt action card.

As long as they're before the bad guy in the initiative order, I allow players to declare an action or manoeuver and put it "on hold" with an if-then trigger. If it's a very time-sensitive or narrow window trigger, I'll apply a greater difficulty or misfortune when it goes off but add fortune dice if it's unexpected by the target.