In every level you are required to arrest a certain number of suspects. Instead of shouting, if you prefer the assault rifle just shoot the suspects four times then shout for compliance. Sometimes they will give up[ others may die. Test this strategy on different people and find which ones may die when you shoot them. Also on any solo or co-operative mission, choose the shotgun and shoot terrorists in the lower stomach region. They will put their hands up immediately, or as soon as you shout at them. If your aim is slightly off, change to tranquilizer (Triangle) and nail them with four to six shots or one magazine. They will fall to the ground, ready to be cuffed.