。
She walked out of the restaurant.
Literal
[topic-は] restaurant [from-から] went-out.
出ていく is a directional compound verb formed from 出る ('to exit') and いく ('to go') — together it conveys exiting and moving away from the speaker's vantage point. The から marks the source ('from the restaurant'). Compare to 出てくる, which would imply coming out toward the speaker. The choice of ~ていく vs ~てくる is a fundamental Japanese deictic distinction that learners often struggle with at first.