I have flown BO-105's, BK-117's, and the Bell 412 on EMS work....you will never....you shall never (imperative tense) catch me in a JetRanger or 350 at night doing EMS work....ever. Promise....take your money to the bank on it. I did not like doing night work in an un-Sas'ed (non-Stab) BK-117 either.
The free enterprise system can be a bit too expensive in lives.
The second engine is no bar from power related accidents but if we operated with CAT A performance (which is a problem if you are doing scene work) at least enroute/cruise engine failures become fairly benign events.
The crux of what EMS operatons should be doing is "to do what is best for the patient" and not money driven alone. So many times, the patient is in a medical facility and stablized....thus delays of a few hours doesn't jeopardize the patients well being and oft times a delay till daylight or better weather would be the best course.
To throw Grandma into a JetRanger or 350 at night or bad weather (or both....worse case scenario) in such a situation borders upon criminal negligence in my view. I would love to be an attorney and specialize in suing EMS operators. It would be a lucrative business nowadays.
To make all the night operations two pilot IFR and Twin IFR machines is expensive but in my view the right thing to do at night outside the built up urban areas. I would accept single pilot IFR equipped twins at night over well light and defined urban areas.
All one man's opinion here....and I am sure there are lots of guys that would argue with my position.