Hi Chopjock, so you have backed your helicopter into the corner, accelerated as fast as possible towards the opposite corner (135m away according to Google Earth and that might just allow you to get to 25-30kts before you hit the far stands) and then 'zoom climbed' at a moment when you guess that your angle of climb will just avoid the stadium roof. Thankfully your one engine (one of my two engines) hasn't stopped because the engines are rather reliable, the climb continues until you get to the top of the stadium roof whereupon you continue an acceleration/climb to a suitable height. If at any time an engine stops (except in the first few seconds of acceleration or on reaching a safe height), the tail rotor quits its job, the rotor head lets go or you just overestimate your guess at what climb angle you were going to achieve, you stand a good chance of killing your passengers. How on earth can you argue that you have reduced any exposure times!!
Cheers
TeeS