I want to propose the following: what if, after being tackled to the ground, it was possible to take your pistol out of a holster (uniform holster or pouch holster) and start shooting while on the ground?
It's somewhat realistic, and cool, and gives people more reason to carry a pistol in addition to their main gun.
Of course it would have to be balanced so its not very overpowered since, as I understand it, it is vital for the xenos to be able to capture humans, and it won't be fun if every capture attempt ends in the xeno dying to a pistol.
So I suppose the accuracy would have to be quite low, and possibly no reloads allowed. So it could scare or stun a wounded xeno who's trying to capture, but would not be enough to kill a xeno on full health who is determined to drag you away.
Also, I imagine for the sake of not making this thing too overpowered, the pistol will also have to be in belt holster, uniform holster or a holster pouch - in all of these cases it's taking up a slot that could be filled with something more useful - pouches, webbing, regular ammo belt. This way, an unga trades carrying capacity for the chance to avoid capture by shooting their attacker.
What do you guys think?