It was purportedly (and probably in actuality) intended as a survival aid to be used after landings and before recovery in the Siberian wilderness, although allegedly was intended as a defensive weapon against in-space attacks by the US space program.
Yes, I guess? But firing a gun inside a spacecraft would be a bad idea… and also firing it while spacewalking would be a bad idea unless you were very sure that you were very well braced & tethered.
Or the gun is just an emergency propulsion system in case you lose your tether…
You could load it with very small, light, or soft pellets, they don’t need to be very damaging to make a hole in a suit which would be near certainly fatal.