die on (someone or something)
1. To die while in someone's care or while in someone's presence, as of a person or other living thing. Get the defibrillator—I refuse to let this guy die on me!
2. To permanently stop working, as of a machine. I have to go buy a new blender because mine died on me today.
3. To die while physically positioned on something. This patient died on the table during a routine surgery because he had an undetected heart condition.
die on someone
1. Lit. [for a patient] to die under the care of someone. Get that medicine over here fast, or this guy's gonna die on me. Come on, mister, don't die on me!
2. Fig. [for something] to quit running for someone. My car died on me, and I couldn't get it started. My CD player died on me, and I had to listen to the radio.