the tv in the first panel: "some guy used this (the pictured crutch) to knock down an escaping suspect"
the wordplay bit: i'm not entirely sure of all the parts, but it's not actually a continuous chain into something obscene, what happened was that the two got into a loop of 来者不善 and 善者不来 (the approaching person is hostile/the friendly people don't come, roughly) and they get pissy cuz they keep spamming the same responses
and if you had to ask me it's not "please unsee it" but rather "you saw nothing" spam.