This is not a drill. In fact, it's a virtual drill. You're looking at soldiers from the 35th Engineer Brigade of the Missouri National Guard as they use a VR training tool known as the Dismounted Soldier Training System.
The system uses motion tracking to allow soldiers to train in a simulated deployed environment, performing simulated foot patrols and clearing buildings in virtual surroundings. It might look a bit silly from here, but it's an incredibly affordable way to train soldiers in all kinds of envrironments -- without them having to leave their military base.
Pictures: US Army photo by Pfc. Samantha J. Whitehead