it's marshaling the facts in a way that would best serve their own interests. >> in officer, ten officers were on leave after a knbc helicopter caught them beating up 35-year-old francis pusok at the end of a pursuit. while he's disturbed by what he saw in the video, john mcmahon of the san bernardino county sheriff's department says it can be difficult for officers to pull back the reins after a chase. >> it is very difficult at times to control your emotions and clearly to control the adrenaline adrenaline. not that that's an excuse but it is certainly a challenge that deputy sheriff and law enforcement officers across the entire country face every single day. >> reporter: a challenge that slager in south carolina can be heard acknowledging right after killing walter scott. >> probably a good idea to jot down your thoughts about whatever happened once the adrenaline stops pumping. >> it's pumping. >> oh, yeah oh, yeah. >> reporter: officers under pressure not just in the heat of the moment but to explain