After falling from a considerable height, you'll find yourself in the sewers. Go right and light up the torch. Then use the case to enter the shaft. You'll make it to a location with piles of shoes. Make your way through and be careful - something will start chasing you soon!
Quickly get to the protruding suitcase. When amidst the shoes, a mysterious creature will start chasing after you, so try to get onto subsequent suitcases as quickly as you can. The protagonist moves through the shoes quite ponderously, so try jumping as far as possible from the suitcases to cover more distance.
Eventually, you'll manage to exit this bizarre room. Go further right, and soon, the long-armed creature will be after you again. You have to RUN. Run straight ahead, slide under the valve and hide in the box in the elevator. Wait until you get to another part of the facility and follow the creature, which will start running after some leprechauns.
Move the box with toys to the left and approach the teddy bear - the plank in the floor will tilt. Go down the plank and proceed right - you will reach a sort of a ladder. Go up and then take the passage on the right. Unfortunately, the being doesn't want to leave the place. Go back a bit and pick a teddy bear. Throw it to the left, hence alarming the creature.
When it goes away to see what's going on, use the drawers to get up and the move the box on the top to reveal another passage. Go down this passage and you'll reach the room with a furnace.