It appears that he lost direct line of sight of the shooting suspect as he circled behind the patrol vehicle seeking cover. It also appears that he probably thought that the shape in the brush on the other side of the rode *was* the shooter ( a not unreasonable assumption, as most often the suspect will run to try and escape) and appeared to be completely surprised when the shooter came up behind him around the patrol vehicle. Remember that the deputy at this point was already suffering the effects of the adrenaline dump AND a gsw. In the end, one nigger goodified and DRT. Nothing of value was lost.