Shocking assault case in an elevator while grocery shopping

https://n.news.naver.com/article/052/0002076767?sid=102

At 2:30 p.m., a woman in her 40s entered the elevator of an apartment in Paju, Gyeonggi Province, and a man in his 20s quietly followed her.

When the door was closed and they were alone, the man suddenly changed.

During the police investigation, the man reportedly said, “I committed the crime because I was dissatisfied with reality.”

I’m dissatisfied with reality

Why assault a stranger with a bat?

I really don’t know