The idea of going in with guns drawn is to stop a shooter before more victims are injured or killed. The strategy is referred to as Locate, Contain, and Neutralize (LCN). This strategy, however, is risky and represents a dramatic shift from the previous more methodological response to hostage situations. Nonetheless, police officers are not certain as to what to expect in hostage situations in which multiple victims and panic play into the shooter's hand. The National Tactical Officers Association endorses the LCN concept and is teaching SWAT units to enter immediately. The effect of new types of mass casualty incidents being perpetrated in domestic terrorism situations on SWAT unit tactics is discussed. 2 photographs