With beach lifeguards doing their part over the past couple weeks to demonstrate just how terrified we should feel swimming beneath their easily-distracted watch, now lifeguards at city pools are making sure we know that they can be negligent too. Yesterday, Luis Peralta, 25, a lifeguard at the Highbridge Pool in Washington Heights, was arrested for dunking a teenager after he joking he would drown anyone who had jumped in while the pool was being cleaned. A fellow teenager told the News, "The lifeguard came in and started drowning the kid. He was basically on top of his head, pushing down with his hands — and he was counting [out loud] up to 5 or 6." Peralta was charged with a misdemeanor for reckless endangerment. The mother of the boy dunked told the Post, "What [the lifeguard] did was very dangerous...I gave him permission to go because I felt safe with him going there, but now I don't feel safe." Just last week, two teens were arrested at the same pool for scuffling with cops when they refused to leave the pool in a similar situation.