Go to rooms 4, zoom right corner of the door, hit the ax to pick it up and store it in the menu, then move into the area and then grab the window by pressing the power cord.
Move to the sink area and zoom in on the water heater, place the power cord into the socket.
Zoom back out and zoom in on the sink, Turn on the hot water.
Zoom out and there will be a code on the mirror, go to the wooden boards and use the axe to break the wooden boards. Zoom in on the safe and enter the code from the mirror (514796, take the key inside the safe and use it to open the door rooms 4
Now continue to the 100 rooms beat level 5 explanation, or back to the 100 rooms beat level 3 solutions