Given the scenario of direct head on confirmed by range closing,bearing not changing, why should anyone contemplate a left turn,as bookworm has suggested ? No, seriously, tell me, there is probably a good reason which my superficial approach has missed.!
That was most definitely
not the scenario I described. If you could see the other aircraft, you'd see the bearing
was steadily increasing. If you simply assume, based on the controller's "12 o'clock opposite direction" limited information, that the other aircraft is on a collision course, the right turn that you suggest would take you into conflict with the other aircraft.