Yeah... I was thinking the same thing.
A good rule of thumb, if some was has you at gun point, there is usually little to chance of disarming or pulling your own weapon unless you're can majorly district them. And since that is kinda a clutch move, don't use it unless it's important to the plot (plot, not your own motivations) to get the upper hand.
In this situation, to guys have to come to terms and work together, so.