How? Because I've heard ALL the testimony, and have taken notes? He was asked who hired him. He said (paraphrase) Michael selected him, and AEG was to pay him. Whatever pay-back arrangement there was, Murray was not a part of, and didn't need to be. That was another contract between Michael and AEG. Doesn't matter if it was "financed," or to be in a lump sum, or what. When asked who hired him, Murray did NOT say, "Michael did." It's very clear on the audio recording.
That is a matter for yet another courtroom, not really relevant for this trial. We ALREADY know that Michael knew Murray and recommended him. We also know that correspondence exists between Murray and AEG, asking for equipment (that has been in testimony in THIS trial). We also have seen Kenny Ortega's email to Randy Philips where he says, ". . now that WE have the doctor on board." (who is "we?")
My POINT is, who hired Murray, i.e. in terms of responsibility, will no doubt be a part of any lawsuits against AEG, but has little or no bearing on THIS trial. And it really IS far from clear. Murray did NOT say, "Michael hired me." I know. I was listening.