Yeah that was depressing. Oh look they have the gun! That means...the predators came back slaughtered everyone and took the gun.
While we are talking about the Predator, can someone explain to me why a badass alien hunter with advanced tech and a ship capable of lightspeed....hunts humans? Really? You're hunting us? I hate to say it but I look at the Predator the same way I look at that dentist that paid 50,000 cash so he could shoot a lion that he knew could not harm him. https://en.m.wikipedia.org/wiki/Kill...Cecil_the_lion. Now I'm not claiming to know what the Predator's real job is, but if we found out that back home on his planet he was a dentist or copyright lawyer would it shock you? No. No it would not.
Now I know what you are about to say "but humans have killed Predators!" . That doesn't mean that the humans were awesome it means that the Predator was lame. If someone tried to kill a Chihuahua and the Chihuahua killed them that doesn't mean the Chihuahua was a badass it means that you were a sad excuse for a human being.
Plus the Predators all have dreadlocks which I'm pretty sure is a form of cultural appropriation.