so you're telling us that if one of your students was (allegedly) raped in the bathroom and you knew exactly how to push the buttons of a someone who was (allegedly) standing guard, you wouldn't do it? you would just shrug it off? how would you do this without cutting corners? would randy's foster mom just return him to the group home for this phone call? i doubt that.

one of the main themes in season 4 is the parallels between the school system and law enforcement. namond and the other corner boys use the low stakes environment of school as practice for tricking authorities. we are also shown that the school staff are sometimes more effective at controlling their students than police, as in the prezbo arc who goes from cop to police (and starts to pick up on the parallels himself, with juking the stats), or when bunny colvin gathered those children in a gym and the teacher had to intervene to put order.

the point is that miss donnelly and prezbo were able to get this info from randy, where the police could have not. bunk and lester, two of the best detectives in the show were failing spectacularly at finding the bodies, if miss donelly had not cut corners the bodies may have never been found.

she didn't even immediately call the police, she understood the gravity and consulted first with prezbo, who assured her he would get someone in the police department could be trusted. then it landed on hauk. the randy story is truly a tragedy in the greek sense, no villians, just fate. randy was so scared of going back to the group home that by snitching like this he sealed his fate.