The system needs built in back pressure against these events. Not just "police accountability" but also a defined system were fuckups like this are expensive organizationally so that the organization has an incentive to prevent them. Something like if you're subject to detention that turns out to be unwarranted you automatically get cash straight out of the police budget. Same deal with having weapons pointed at you.

This also helps provide restitution to victims who would otherwise just be screwed out of their time and legal defense fees