rentre means to return, not just to enter
I think that the translation as they have is correct, but the grammar is poor. J'entre would be better it seems to me.
"Return IN?" That is not an English translation; we wouldn't say it like that.
Thats my question also: what is the difference between j'entre and je rentre?
The dictionary says 'return' is 'retourne' and 'rentrer' is 'to go/come back in'. Now I am confused!
I would always say I come back into as it is talking about going from one place into another. In would be used only if I were already inside.
We wouldn't say "return into the shop," we would say "I go back into the shop," but this odd translation emphasizes the way that the verb works within the sentence.