I understand your scenario; but it is a specific setup.
Keep in mind, even randomness, properly set up, is controlled by specific parameters. Meaning; Randomized spawn locations doesn't mean "anywhere, everywhere, at anytime". Even randomness, properly executed, is still controlled.
Very simply put, the player walks into a trigger zone, and based on a random number generated at mission startup, a tango may spawn at one of 4 locations. But none of those locations would allow the tango to spawn on the end of your rifle.
Even randomness needs a leash.