Master switch doesn't affect ignition. Well done on flagging that you did something wrong, you didn't endanger anybody, but you might want to spend a bit of time with the POH? Your check pilot should probably have made a point of asking if the switches are off as well mind you.
Personally, I always have a checklist with me, if only for ground checks. I can't say I agree with somebody who prefers a rusty pilot to work from memory.
Sounds like idle RPM may have been a bit low. Easily adjusted, but best speak to a ground engineer before it's flown again, AND make a tech log entry.
G