Monkeys are intelligent animals among the animal group. They could easily learn many things like human. In the video people are offering  a gun to monkey and it shoots them. Monkeys are haplorhine primates, a group generally possessing tails and consisting of approximately 260 known living species. Many monkey species are tree-dwelling , although there are species that live primarily on the ground, such as baboons. Most species are also active during the day . Monkeys are generally considered to be intelligent, particularly Old World monkeys.

The AK-47 is a selective-fire, gas-operated 7.62×39mm assault rifle, first developed in the Soviet Union by Mikhail Kalashnikov. It is officially known in the Soviet documentation as Avtomat Kalashnikov.After the war in 1946, the AK-47 was presented for official military trials. In 1948, the fixed-stock version was introduced into active service with selected units of the Soviet Army. The AK-47 was designed to be a simple, reliable automatic rifle that could be manufactured quickly and cheaply, using mass production methods that were state of the art in the Soviet Union during the late 1940s. The large gas piston, generous clearances between moving parts, and tapered cartridge case design allow the gun to endure large amounts of foreign matter and fouling without failing to cycle.  

This reliability comes at the expense of accuracy, as the looser tolerances do not allow for precision and consistency. All of them ran away just after the monkey starts firing the AK-47. They were firstly  teasing the animal but as the monkey starts firing they became black and red and ran away.