I'm going to take a wild guess (but no wilder than suggesting the cyclist was killed because he was on a bike): a big part of the offense was CWB, a variant on DWB. Look it up if you don't know what that means. That + deaf (not responding immediately to police call), + seizure condition/medication (unusual affect/manner) and an inexperienced and poorly trained officer, and you get that kind of tragic but completely preventable situation.