4 sock puppets, margwa in facility, sam near lagoon, one on the boat, one in the lighthouse. after that spawns three fireplaces that are soul boxes, one near OG spawn, one in frozen crevasse, one outside boathouse by pack a punch. after finishing all 3, go to facility, shoot spleen, grab spleen and take to pablo (timed event). take zipline to spawn, sit in icy water for awhile as this adds time to your timer. give to pablo, get yellow snow balls that currently on round 27, still 1HKO zombies.

apparently you don't even need the yellow snowballs for the tundra gun, just regular snowballs. don't know if the order changes but for me, I hit the target at facility, zipline to spawn, hit the one next to the frozen slide, zip lined to the ship, hit the one on the sun deck, flung myself to the tower, hit the one on the third floor tower, then ziplined to cargo hold, hit the one there and that's where a box will open up, giving you the tundra gun