Obviously most combat maneuvers conducted by the infantry are undertaken while under fire and many tactics exist which have the purpose of minimalizing friendly casualties. Advancing under fire begins with the infantryman's training. He/she is trained to keep a low profile (hence the dodge roll) while advancing and to move from cover to cover, snapping shots off at targets as they present themselves. The SAW man plays a critical roll while the squad is advancing. He/she finds himself a good firing position and lays down cover fire onto enemy heavy weapons positions and suppresses any enemy positions that provide his/her sqaud with problems. The buddy teams within the squad also aid the squad when it is advancing under fire with one buddy prodiving cover fire (high volume spray fire) for his partner while he runs forwards to the next cover. Advancing under fire is actually not as common as one thinks as assaulting an enemy position (which would require advancing under fire) is only undertaken when a military force has not been able to remove the enemy from its defensive positions by any other means (artillery, massed gunfire....etc). As put by Southern General Robert E. Lee "The only way to claim a piece of land is to force the other guy out at bayonet point".