When preparing to breach and clear a room, taking precautions determines your success and lowers the chance of an injury or death. Examine the building you plan to enter. Note all possible entry points, such as doors and windows. Estimate the number of threats in the room and arrange your team accordingly. Assign three or four team members to clear each room, if possible. Consider the threat. If the threat expects your arrival, the building and room is likely guarded or booby-trapped. Equip each team member with a light source or night vision goggles. Lights in rooms can turn off unexpectedly.
Soldiers and police prefer to clear a building from the top town, because this is usually the safest method. If possible, use a ladder to climb through a window, or rappel from the roof down through a window. This approach works best if the threat is unaware of your presence. Because upper-level entry is usually difficult, entry through the door is the more common. Shooting a door's hinges with a shotgun allows for quick and effective breaching. Do not use small arms to shoot the door's hinges or lock unless absolutely necessary. Bullets can ricochet and injure or kill you. An axe or ram is also effective when breaking down a door. Kick the door down, if necessary. Kicking is the least preferred entry technique because it takes several attempts to break the door.
In a combat situation, throw a frag grenade into the room as hard as possible. This prevents enemies from throwing the grenade back. When you toss the grenade, yell "frag out" so friendly soldiers are aware of the danger. If an enemy tosses a grenade your way, yell "grenade." Police generally do not throw grenades into rooms but instead focus on entering the room immediately after breaching the door.
Send one team member into the room first to clear any immediate threats. Have a second member enter immediately after. The second member clears threats on the opposite side of the room. Always have one team member dedicated to clearing one corner or section of the room. In rooms with hallways, send one member straight down the hall. Have two other members investigate the rooms on each side of the hall.
Once a room is safely cleared, check the bodies of all enemy combatants to verify that they are no longer a threat. Disarm wounded enemy combatants. Evacuate any non-combatants and request immediate medical care for the injured. If enemy combatants or threats choose to surrender, take them into custody. Search the room for further threats, traps or evidence. When the room is clear of enemies and other dangers, it is safe to exit. If commanded by your leader or officer, leave a sign to mark the room as clear for other team members.