The caretaker shuffled into the interior of a vessel (7)
I believe the answer is:
janitor
'the caretaker' is the definition.
(I've seen this before)
'into the interior of a vessel' is the wordplay.
'into' becomes 'jani' (I can't justify this - if you can you should believe this answer much more).
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'interior of' means to look at the middle letters.
'a vessel' becomes 'roro' (short for roll-on/roll-off).
The middle letters of 'roro' are 'or'.
'jani'+'t'+'or'='JANITOR'
'shuffled' is the link.
I am not very happy about this link. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for janitor that I've seen before include "Person looking after building" , "One employed to clean and maintain a building" , "Caretaker (mainly US)" , "Caretaker or doorkeeper" , "(In Scotland) school caretaker" .)