But, despite all that, whether or not anyone here believes it, there's a great core of decency in most Chicagoans, regardless of their color, their ethnicity, or their neighborhood. I've never come across a situation precisely like this, but as in any dangerous situation, you need to weigh the possible upside and downside against your sense of right and wrong.
However, I read Deanimator and ilbob as painting the whole city with a pretty broad brush, saying effectively, "It's Chicago . . . just walk away and don't call the cops." I disagree.
If there was a core of decency in Chicago voters as a whole, they would have voted the Daley crime family and his cronies out of office many years ago.
Its true that there are areas of the city that are safer than other areas. The incident under discussion did not happen in an area that anyone would consider "safe".
As a whole, getting involved with Chicago PD is a serious risk, especially in those neighborhoods. Less so in safer areas.
If I am a passer by to such an incident, I am going to make tracks and only when I am a long and safe ways away am I going to even think about doing anything else, including calling 911.
BTW, any place but Chicago (or a few of the more nefarious suburbs - you being in LE probably know the ones I am thinking of - they are the ones with dozens of indicted cops), I probably call 911 - on my way somewhere safe.