I was in a solo ZM : Compound game, on the Day 6, I slayed the boss.
It showed 4 zombies remaining, I killed 4 and went under the Helicopter waiting for it to come down.
Then suddenly a couple zombies appeared and killed me.
Since I had killed the 4 zombies remaining that it showed, the Helicopter had came down, but I didn't have any lives left so I was stuck in the 'YOU ARE A ZOMBIE' screen.
You can clearly see in the images that the Helicopter has landed and there should be no more zombies left.