Says Donald Trump, immediately springing back after "his bodyguards race to surround him on stage minutes after he brushed off last night's Chicago racist violence as 'planned attack' by 'professional wiseguys.'"
The quote in the headline is my transcription from the video at the link (which goes to The Daily Mail). Just before he says that, he says, "'Thank you for the warning. I was ready for 'em, but it's much better if the cops do it, don't we agree?," which is quoted in the article. The Daily Mail headline says that Trump is "left visibly shaken," but it is my observation that Trump does not flinch and displays solid physical courage. And by the way, the "bodyguards" are Secret Service agents. They surrounded him because an audience member had gotten onto the stage and thrown something.
The line "it's payback time" could be misinterpreted and used very aggressively against Trump (as part of the theory that he's against various groups and out to damage them), but I think that, in the context, it's obvious that he's answering his own question: Why am I doing this when I had such a luxuriously comfortable life? The answer is that he did well and he feels an obligation to give back.