slip out

/S L IH1 P AW0 T/
verb
  1. 1

    To leave quietly, and unnoticed.

  2. 2

    To go out for a brief moment; pop out

  3. 3

    To be said or revealed by accident.

    โ€œI was talking to Jim, about Paul and Ethel, when it just slipped out about their possible divorce. I'm sorry.โ€

Source: https://en.wiktionary.org/wiki/slip%20out