He didn't interfere (he asked some questions as a certified medical professional) and he didn't make the situation worse. The officers made the situation worse,

He didn't interfere (he asked some questions as a certified medical professional) and he didn't make the situation worse. The officers made the situation worse, and he probably made things better for the guy in question -- would you want those particular violent abusive officers spending the next little while with their full attention on YOU? Ideally they'd be in jail, but if he distracted them for a while the guy's probably better off -- maybe the author took a beating the guy would have received.