Exploit with energy drink lands someone in the Tower (9)

I believe the answer is:
beefeater
'someone in the tower' is the definition.
'beefeater' can be an answer for 'someone' (beefeater is a kind of someone). I am not sure about the 'in the tower' bit.
'exploit with energy drink lands' is the wordplay.
I cannot quite see how this works, but
'exploit' could be 'feat' (synonyms) and 'feat' is found within the answer.
'energy' could be 'e' (physics symbol as in E=mc2) and 'e' is present in the answer.
'drink' could be 'beer' (beer is a kind of drink) and 'beer' is found in the leftover letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for beefeater that I've seen before include "Royal servant" , "Tower of London guard" , "One might guard" , "royal bodyguard" , "Bodyguard of the British monarch" .)
