[RunawayEngineer]

Dealing with mentors is tricky - it's a volunteer gig, so you don't have the freedom to demand much that they don't want to do. Respectfully handling disagreements is paramount.
I find the phrase "Show me in the manual where _________ " helpful when I am confident that the rules support my position. At the very least, it will reveal if someone is simply being bullheaded (they won't look in the rules, but will continue arguing). It changes the conversation from arguing on what you remember the rules to be to the actual wording of the rules. This puts you on the track to an answer, rather than on track to the better arguer.