hay wats up zomfans KillemZombies here,
I was playing Buried today and round 1, hit the box and got
ballistic knife. the moment I pick it up the green smoke goes off.
then after the 4th round after using just the ballistic knife i got the green smoke at the end of
the round again like i just unlocked something. Ill try to do more research and try to find out what the
green smoke was for but i did play again after and did get the ballistic knife on round after already hitting
the box and no green smoke. so i think you need to get it on round 1.
more to come and here is A VIDEO ------>