I'm sure there was info exchanged between Bobby D, Marshall and Stan that wasn't written in. The cell calls and texts were a flying. Also, Bobby D was likely the one to call Marshall initially and may have given him the brief run down in transit.
And btw, there's no way Mary could've arrived at the hospital 8 minutes after getting shot. The laws of physics would have to have been broken.
At least 3-5 minutes for EMTs to arrive, at least 5-10 minutes to stabilize Mary for transit, at least 5-10 minute transit time. At the minimum we're looking at 13-18 minutes. Gotta love Hollywood

I would've liked to see the scene where Marshall finds out Mary was shot...