Don't be found with 〜てはだめだ
Grammar Explanation: Must not do with 〜てはだめだ
While telling ghost stories at night, Rize relays the tale from her childhood, of a frightened servant walking home one night. Rize says the culprit was her, practicing sneaking around and crawling through the bushes.
- 「バラしちゃだめじゃん!!」
- "Don't be found!!"
Note that じゃん is a short form of じゃない, the negative of だ.