Put in prison one after the other, so we hear (6)
I believe the answer is:
intern
'put in prison' is the definition.
(I've seen this before)
'one after the other so we hear' is the wordplay.
'one after the other' becomes 'inturn' (I've seen this in another clue).
'so we hear' indicates a 'sounds like' (homophone) clue.
'inturn' sounds like 'INTERN'.
(Other definitions for intern that I've seen before include "Shut up" , "Incarcerate without trial - a junior hospital doctor?" , "Novice gaining experience" , "Imprison (eg, alien) as a precautionary measure" , "Confine the hospital resident" .)