A family of Microsoft word processing software products for creating web, email, and print documents.
The middle of the search expression is
[!”^13]@
Inside the brackets, the exclamation mark ! means "not". So the grouping in the brackets will match any character that is not a closing quote or a paragraph mark. The @ at the end means "any sequence of characters that match the preceding expression".
So the whole search expression matches everything between an opening quote and the next paragraph mark, except a closing quote. In your example, the closing quote in the middle of the paragraph causes the expression to stop matching.