Marines with Bravo Company, the 2nd Reconnaissance Battalion (2nd Recon), enter a room during close quarters combat (CQC) training.
During such training, operators learn to quickly make entry into a room and identify and engage threats.
CQC training often starts with the students moving relatively slowly through the specially-constructed shooting houses with unloaded weapons (dry firing) while they hone the basics of such skills as muzzle discipline, firing arcs, room entry and dealing with corridors and multiple rooms and floors.
Training then proceeds onto the use of simunition and eventually escalates to full speed assaults with live ammunition being fired.