“It was one of the most severe beatings they’ve seen on tape,” an FDNY insider said, recalling the reaction by brass who viewed video of the bloody fisticuffs. “They can’t believe one of the guys wasn’t killed.” The tape shows Adam Soler, 35, of Engine 68, being held down by two firefighters from Rescue Co. 3 and repeatedly kicked by a third, said sources who were told about the video. “Someone grabbed his head and started pounding it into the pavement,” one said. Yet two months after the June 6 melee, no one has been arrested or fired.