"彼女は彼に隠れてお菓子を食べている"
- She is hiding from him and eating sweets.
- She hid from him and is eating sweets.
She is hiding from her son as she eats sweets.
- お菓子を食べながら、息子に隠れている。
She makes sure to hide from her son while she eats sweets.
- お菓子を食べるときは、必ず息子から隠れて食べている。
She makes sure to hide so that her son does not see her while she eats sweets.
- お菓子を食べるときは、息子に見つからないように隠れる。
She is hiding the snacks from him in order to eat them by herself.
ご質問ありがとうございます。
この場合、「彼女は彼に隠れて[お菓子](https://eikaiwa.dmm.com/uknow/questions/6041/)を食べている」と言いたいなら、英語で「She is hiding the snacks from him in order to eat them by herself.」と言えます。
ご参考になれば幸いです。