They cut the roof of the BMW off... presumably to remove the Driver...
The Police RIder was on an unmarked Police Motorbike and responding to a 999 call.
http://www.dailyecho.co.uk/video/2275230984001/?ref=vidshare
Looking at the video it would appear that the Silver BMW was attempting to perform a right manoeuvre across the carriageway into the Petrol Station and the unmarked Police Motorbike went into the Driver's side of the car, possibly causing the injuries to the car driver.