) ( 3 ) , " fear of hostile military or terrorist activity " means that a veteran experienced , witnessed , or was confronted with an event or circumstance that involved actual or threatened death or serious injury , or a threat to the physical integrity of the veteran or others , such as from an actual or potential improvised explosive device ; vehicle - imbedded explosive device ; incoming artillery , rocket , or mortar fire ; grenade ; small arms fire , including suspected sniper fire ; or attack upon friendly military aircraft , and the veteran ' s response to the event or circumstance involved a psychological or psycho - physiological state of fear , helplessness or horror . Generally , veterans are presumed