Author in hurry to disappear? Yes, once! (7)
I believe the answer is:
rushdie
'author' is the definition.
(I've seen this before)
'hurry to disappear? yes once' is the wordplay.
'hurry' becomes 'rush' ('rush' can be a synonym of 'hurry').
'to disappear? yes once' becomes 'die' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'rush'+'die'='RUSHDIE'
'in' is the link.
(Other definitions for rushdie that I've seen before include "Salman -, Midnight's Children author" , "See 23 Across. 23 and 22 Across: Author under Islamic sentence of death for blasphemy" , "'Salman ..., author (7)'" , "Salman - - (lit.)" , "Salman -, Br. author" .)