Get everything out of tower that's going up (3)
I believe the answer is:
gut
'get everything out' is the definition.
I can't tell whether this defines the answer.
'tower that's going up' is the wordplay.
'tower' becomes 'tug' (something that tows).
'that's going up' shows that the letters should be reversed in order (in a down clue, the letters are written upwards).
'tug' backwards is 'GUT'.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for gut that I've seen before include "strong feelings" , "Thread made from animal intestines" , "Part of intestine" , "Paunch" , "The stuff of a violin string" .)