It would be a quick ambulance, no doubt about it. But holding slides with a patient in the back? Eh....
There's also the matter of running costs, and maintenance. Worst scenario to happen if something breaks, it's going to be alot more expensive than it is on what's currently being used.
V6, although a better choice for that level of power would be a V8. Easier to drive, better throttle response, cheaper to maintain.