I think it's a simple problem.

A man living on the 10th floor takes the elevator down to the 1st floor every morning. However, on his way back, he gets off at the 7th floor and walks the remaining 3 floors up. Only on rainy days does he take the elevator all the way up to the 10th floor. Why? This is a 'Sea Turtle Soup' riddle I saw on TV this morning. (I didn't remember the details, so I found it online and brought it here.) 【UPDATE】 The answer has been found. However, if there are still people who want to think about it themselves, I will continue the discussion if you ask questions.