Review cross section making exit from stage (8)
I believe the answer is:
trapdoor
'exit from stage' is the definition.
(a theatre stage might have a trapdoor)
'review cross section' is the wordplay.
'review' shows that the letters should be reversed in order.
'cross' becomes 'rood' (term for a crucifix).
'section' becomes 'part' (synonyms).
'rood'+'part'='roodpart'
'roodpart' written backwards gives 'TRAPDOOR'.
'making' acts as a link.
(Other definitions for trapdoor that I've seen before include "Means of access set in floor or ceiling" , "giving access to roof, perhaps" , "Horizontal access panel" , "stage opening?" , "Hinged flap" .)