Sister's house in New York accommodating fugitive when beginning escapes (7)

I believe the answer is:

nunnery

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'sister's house in new york accommodating fugitive when beginning escapes' is the definition.
I can't tell whether this defines the answer.

'sister's house in new york' is the wordplay.
'sister' becomes 'nun' (I've seen this before).
'house' becomes 'er' (I am not sure about this - if you are sure you should believe this answer much more).
'in' indicates putting letters inside.
'new york' becomes 'ny'.
'er' placed into 'ny' is 'nery'.
'nun'+'nery'='NUNNERY'

Can you help me to learn more?

(Other definitions for nunnery that I've seen before include "sisters' place" , "Religious house for females" , "Convent" , "Hamlet to Ophelia: 'Get thee to a . . . . . . .'" , "Religious establishment" .)

I've seen this clue in The Telegraph.

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