10 min in survival mode




15 min in CO-OP mode


To unlock the achievement in CO-OP mode, you don't need any other player.
Just select multiplayer mode, host the game, launch it and ... try to survive !





OK ! ... How did you do that dude ?

Well, it was very simple in fact.
I unlocked those achievements while playing on "Savage Waters" map.


First Way (not easy)




You can stay inside the immersed plane.
Good News : Those unfriendly fishes are not able to come in
Bad News : Oxygen and ammo crate are not so close, so you'll have to swim like a dolphin to reload




Second Way


The ammo crate is near the immersed boat (remember that).





Go at the bottom of the cliff to find the oxygen (from the spawn point, just behind you, just dive in the mine field)






Now here's the trick : there is a cavity in the cliff where you'll be safe (almost).
It is straight in front of oxygen bottles (hard to see it, but go forward, and you'll find it)






Oxygen is not a problem now !

Only small sharks will be able to reach you (maybe the great white shark too, but it's really hard for it to get you).
Kill all incoming small sharks.
When you're out of ammo, quick rush to the ammo crate (swim close to the floor) and go back to the cavity.
Always keep an eye on the radar.

You should unlock the achievements easily !




I hope this will be helpul

Enjoy !