Don't have to leave the building (2,7)
I believe the answer is:
go without
'don't have' is the definition.
The definition and answer can be both to do with ownership as well as being verbs in their base form.
Perhaps you can see a link between them that I don't see?
'leave the building' is the wordplay.
'leave' becomes 'go'.
'the building' becomes 'without' (I am not sure about this - if you are sure you should believe this answer much more).
'go'+'without'='GO WITHOUT'
'to' is the link.
Can you help me to learn more?
(Other definitions for go without that I've seen before include "Suffer a lack of" , "Want" , "give up" , "pass up" , "be denied" .)