What does the cryptic crossword clue "Quickly read ‘Joins in matrimony’ aloud in shock (10)" mean?

The definition is "shock". The wordplay uses a homophone (sounds like). Homophone of “scanned allies” The answer is SCANDALISE.

Quickly read ‘Joins in matrimony’ aloud in shock (10)

Guardian Cryptic #29463 | 23 Across | 2024-08-16 flower