For the first 3 rounds, just use the pistol and stab. On round 4, buy the M14 off the wall.
Either round 5, 6 or 7 will have dogs coming after you. After you kill the dogs, open the downstairs door and keep opening the doors until your outside.

The box usually starts here. After you turn on the power, link the teleporter.

When you can't handle the zombies, teleport and you'll be in a sniping spot with a pack-a-punch machine.

Leave a crawler and try your luck in the box for a ray gun or akimbo pistols.