Well, he came in all on turn 2, forgot what he used I think he had something else, it was around the time when apocalypse was first released and we had one big game at the store.
The tables could barely fit everyones armies. I don't quite remember all the details, he killed roughly 300 gaunts that was layered in front of the enemy army. About 6 tyranid players were on that side with orks and others.
That's all he got to kill IIRC, because everyone was firing at the vehicles and the 20-some titans that were involved. Nobody bothered to clear a spot for him to get to the back. Not that his assassins would have done much there.