ambulance

A vehicle equipped for transporting the injured or sick. They contain emergency medical equipment and are staffed by emergency medical technicians. They have loud sirens and flashing lights to tell other drivers to get the hell out of the way. And for goodness sake, if there's one coming up behind you... GET THE HELL OUT OF THE WAY! Someone's in trouble back there, and that takes precedence over anything you're doing. 

Saw a guy race an ambulance through a stop light once. How arrogant and entitled can you get?

Am"bu*lance (#), n. [F. ambulance, hopital ambulant, fr. L. ambulare to walk. See Amble.] Mil. (a)

A field hospital, so organized as to follow an army in its movements, and intended to succor the wounded as soon as possible. Often used adjectively; as, an ambulance wagon; ambulance stretcher; ambulance corps.

An ambulance wagon or cart for conveying the wounded from the field, or to a hospital.

© Webster 1913.