'PM 10:03' is a 'Yoo Ji-min's text message' in White Day: A Labyrinth Named School (Remake).
It is exclusive to the PC/PS4 remake version.
You can see this message when you play the 'Yoo Ji-min' route.
It is found in the Messages Menu. (Mobile Phone - Gameplay element feature)
How was the orientation?
Do you like the school?
How's the food there?
When I go there, I'm going to make your favorite, Bulgogi.
학교는 마음에 들고?
음식은 입에 맞는 지 모르겠다...
엄마가 올라가면 지민이가 좋아하는 불고기 해 줄게.