First that is assuming they get full control of the firearm back. There is an interesting dynamic that occurs that I have noticed in my Kali training with knives and firearm weapon retention as a LEO. When someone tries to control/take "your" weapon you will instinctively use both hands to maintain it in your control even if you can not clear a malfunction/use it offensively. Your brain basically says "better to keep a grip on this myself than let 'them' take it and turn it against me." This causes you to use both hands on the weapon for control (gross motor function) rather than try to rack against the opponents dual hand control on the slide/frame (fine motor function).