Taking a stage cylinder with 36% to a depth of 35m without decent training is asking for trouble. Whilst the ppO2 at 35m would only be 1.62 bar and it is unlikely to provoke an O2 hit within a few seconds, you are asking for serious trouble if you use it that deep.
Taking a stage negates the original premise that it is a recreational dive 
My answer is: do a decent training course as you are unlikely to find out all the dangers until it's too late if you don't.
Cheers, Chris
The man who's more anal than Kirstie - Turbanator
Speshul - Steve Summers