I am pretty sure that Izumi is going to join Gant's "team" ... but that is just so much bullshit. He really should just die for all that he has done, and STAY DEAD.
The dumbest thing about their duel is how Izumi expected to have a good and fair duel by pitting a semi-automatic against a gun with a delayed effect. Of course he wouldn't be able to shoot without getting shot! Was he even a Gantz veteran at all?
It's a good thing that his dumb ass kept on wasting bullets before the fight so he wasn't able to kill Tae in time.