Doctor made realities go away (13)
I believe the answer is:
dematerialise
'go away' is the definition.
('go away'->'dematerialize' is in my internal thesaurus and 'ize'->'ise')
'doctor made realities' is the wordplay.
'doctor' indicates an anagram.
'made'+'realities'='maderealities'
'maderealities' with letters rearranged gives 'DEMATERIALISE'.
(Other definitions for dematerialise that I've seen before include "Lose physical presence" , "Vanish" , "Cease to have physical presence" .)