Another simple one
Fly back to base single engine and carry out a textbook (I hope) single engine landing)
For your information it was not totally unheard of to bring an AS 355 back to base on one engine following a chip warning.
Next question.
Oh, an addition!
we would never be full tanks in an AS355 because we wouldn't have been Perf A (which for us over the city is a requirement.!)
In the MD 902 (and I'm sure the EC135) we can operate with full tanks most of the year (if a, we can be bothered to fill up the last 190 lbs and b, we haven't got a particularly lardy crew on board!)
But the same would apply, so far, thanks to P&W's quality engineering, we haven't had to find out for real.
Remember, we have to operate to performance A standards all the time (and I'm pretty sure that at 500 ft above the highest obstacle in my vicinity the 902 would fly away quite nicely).