As most of you know PHD Flopper is not in Buried, or any other of the maps as a buyable perk, but it is in the game. PHD is basically like the quick revive (where you need to revive 15 players in a game) except instead of reviving (obviously), you have to take a certain amount of fall damage. As I was playing on Buried I kept getting on the roof tops and kept jumping off, when maybe after the 20 time a green light came from my character. After that I shot the ground a few times with the Ray Gun and I took no damage, then I dolphin dived off of a roof and the explosion came from my body. But later in the round I died because I fell from a high ledge...

So what is confirmed:
PHD is possible to get.
It does prevent you from killing yourself with explosions.
When diving you explode and damage near by zombies.

What is not confirmed:
This version of PHD prevents you from taking fall damage.
This is permanent.
How much fall damage is needed in order to receive PHD.
And how long it lasts, or what makes it go away.

Other information:
Dead Shot Daiquiri is possible to get by shooting about 40 heads.
Quick Revive is possible to get by reviving 15 players in a game.

Hope this helps!!! And more information will be posted as time goes by.