YOU SAID:

He who walks down the street, must walk back up the street.

INTO JAPANESE

彼は、通りを歩く人は通りを戻って歩く必要があります。

BACK INTO ENGLISH

You must walk him back as a person walking down the street.

INTO JAPANESE

彼は、通りを歩きながら人として戻って歩く必要があります。

BACK INTO ENGLISH

You must walk him back as a person walking down the street.