Please read carefully, model aircraft NEVER have the right of way over a full scale aircraft. NEVER, EVER. I don't have time to pull the regs (FAR's) at this moment, actually my books are at work. It doesn't matter where the helicopter was, why it was there or what altitude, it has the right of way.
There is a bit of a problem with the definition of right of way. The right of way rules in the FAR's do not mention models. The AMA and AC mention that we should give right of way, but do not explain that fact. Actually we can only land or fly at a low altitude when we hear an aircraft, which I believe is the intent of the AC and the AMA rule. I don't know what else you can do other than turn away if discovered at the last moment. That is not the meaning of right of way in the FAR's. That actually comes under see and avoid. Right of way is when you give way to an oncoming aircraft, to include which way you turn, etc. There is no time for a model to do that and no rules on how it should be done.