To achieve the fifth ending:

1. Pick up a ticket in the classroom.
2. Go to the floor where there is a painting with a doll, there are 3 fragments there. The doll's hand literally points to the location of the fragments:

First fragment: near the boards in the corner by the entrance door.

Second fragment: in the boards to the left of the painting.

Third fragment: on the ceiling in the pipes, near the door from which a ball will roll out.

3. Go to the floor, where there is a piano and a bathtub on the stage. There, you need to collect 3 fragments of the song structure. After collecting all the fragments, you need to play the piano.

The first fragment is next to the chest of drawers, where you need to pick up the ladder.

Second fragment is next to the seats, on the side of the piano.

The third fragment is near the closet in the children's room.

4. Go to the floor where there are 3 painted doors. You need to enter the number combination (1615183351614), where each number represents the corner number to go to. After selecting the correct corner, you will hear a knock on the door. The corner with the painted clock is number one, and subsequent corner numbers proceed clockwise.

Video with the introduction of the combination:

Photos:

Classroom ticket

First fragment of the doll painting

Second fragment of the doll painting

Third fragment of the doll painting

First fragment of the song structure

Second fragment of the song structure

Third fragment of the song structure

Corner numbering (thanks to the community)