In the army, especially? That's right (3)
I believe the answer is:
yes
'right' is the definition.
(right can mean yes or okay)
'in the army especially? that's' is the wordplay.
'in' indicates a hidden word.
'YES' is hidden within 'army especially thats'.
(Other definitions for yes that I've seen before include "Confirmation" , "3 across" , "Indeed" , "Affirmative answer" , "Positive reply" .)