The Wikipedia article does:

> After several hours and several drug injections, Jackson was still unable to fall asleep, and, according to Murray, was repeatedly asking him for "milk", a nickname for the powerful surgical general anesthetic propofol, which Jackson had used in the past as a sleep aid. At 10:40 a.m., with Jackson still not asleep, Murray relented to his requests and injected him with 25 milligrams of propofol diluted with lidocaine. With Jackson finally asleep, Murray testified that he left his bedside to go to the bathroom, and after returning two minutes later, discovered that Jackson was not breathing and had a weak pulse.

Thanks! TIL that Propofol has a nickname "Milk of amnesia". MJ asked more milk which meant more propofol.