I think you'll find that THAT possibility has already been examined. See Below.samaritan.squirrel said:Unleash Samus Aran on him.
Personally though, I'd go for the irony. Heart Attack after Cortana and him do the virtual horizontal mambo?
Impaling on a spartan laser fired by some grunt?
Or the metaphysical option, send him back in time with a DeLorean and let him live himself to death?