Friend when she was in a poor part of Africa noted that the local cell tower had two armed guards. Her host told that a few years prior they had a single guard. Thieves came and killed him with a chainsaw and stole the generators. So now the guards are armed with machine guns and there are two of them.
Are you sure they were using machine guns? That would either imply they are part of the military of zimbabwe's gun laws are very loose.
I bet it helps to yell "Stop in the name of the law!" when thieves with chainsaws run towards you.