To achieve the fourth ending:

1. Take a ticket in class and solve a puzzle in the same room.
2. Get the key to the wardrobe.
3. Take the letter in the wardrobe and hang up your coat.
4. Take the number “11” and if the radio starts playing, head for the exit.

Tricks

1. Instantly skip the first monologue and shortcut to the door

Explanation: After loading the first location, it's not necessary to move forward. You can cut the path by sticking to the crate and passing between the chair and the column. This way, you can skip the first monologue instantly and immediately open the door.

2. Movement during cutscene

Explanation: After solving the puzzle in the classroom, you need to keep control and move forward. If you memorize the route, you can leave the classroom immediately after the cutscene ends and slightly shorten your path.

3. Large hitboxes

Explanation: It's not necessary to approach the object closely; you can almost always maintain a considerable distance and still interact with it, which will help save time.

4. Instant monologue skip at the final door

Explanation: If you stick to the right side during the monologue activation, the skip button should appear immediately. This will help save a lot of time and activate the ending faster.

Example of a run using these tricks: