we were playing Two Betrayals co-op on Legendary,and on the second pulse generator,i had no shotgun ammo and only one rocket,and a swarm of Flood ambushes you when you destroy the generator when you have no shields,so i had my cousin warp me back into the exit tunnel right when i destroy the pulse thing. we ended up appearing behind a group of frozen Flood. we threw plasma nades on them and they wouldnt explode and the flood wouldnt move until we passed a certain point,so we unloaded all of our remainig rockets into them and threw all of our nades,and then jumped in the middle of them and watched everything go up in a massive explosion of Spartans,Flood and Flood bodyparts. there was so much going on that the game froze. you should go try it