Car involved in collision while at mechanic’s, any advice?

Hi all, this is in California. Dropped off our old but still fully functional 2006 Honda Civic for oil change and brake check. While the mechanics had the car they were moving it across the street and a police car (not with its lights/sirens on importantly) came way too fast around the corner and hit the driver side rear tire area.

The damage isn’t massive but not negligible either, although the car still seems to drive okay from what they said. Given the age of the car though I’m expecting the mechanic’s insurance to come back with a total salvage offer rather than a repair, waiting on their adjuster to finalize their report. Not sure if it matters but I haven’t taken possession of the car at all since dropping it off.

Since the mechanics had complete control of the car (I wasn’t even there when it happened) I haven’t involved our insurance at all. If there’s any reason we should involve our insurance I’m all ears though!

Anyways, wondering if there’s any advice people have for making sure their insurance offers the maximum amount possible? Very annoying to drop a car off for basic service and end up in this situation.