What does the cryptic crossword clue "Attack with gun whilst I pop out (6-4)" mean?

The wordplay uses an anagram. anagram of WHILST + I + POP = PISTOL-WHIP The answer is PISTOL-WHIP.

Attack with gun whilst I pop out (6-4)

Times Cryptic #28539 | 5 Down | 2023-03-01 flower