When you are on any floor of one of the two multi-floored military buildings and there is empty space below the floor (a room) there is a random and common possibility it will act like you fell from an extremely high place, however just by standing there, and not going anywhere. This will cause broken legs, ruined pants/boots and a very high chance of dieing. This has happened to myself and another player multiple times already (6+) within the last few days. This is a very serious issue. An image has been supplied so you know exactly the buildings which this occurs in.