I Have Observed a Photon at One and Only One Mirror

In whichever universe, palox can record and transmit back to david intermediate result. It must be the same message in either case because distances d and u are long. Palox does indeed have time to do all this, because he's got a fast brain. But very soon after he sends that message, the message that says, i have detected the photon striking one of my mirrors, and only one of my mirror, he then sends another message. And he repeats the experiment again and again, as good scientists do, sending message after message back to David. In other words, roughly half the time detector one is activated and half the time detected two, is because the photon only ever takes one