Quietly take the available seat on the left (5)

I believe the answer is:
steal
'quietly take' is the definition.
'steal' can be an answer for 'take' (stealing is a kind of taking). I am not certain of the 'quietly' bit.
'available seat on the left' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'seat' is 'stea' which is within the answer.
'left' could be 'l' (common abbreviation) and 'l' is found within the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'the' is the link.
Can you help me to learn more?
(Other definitions for steal that I've seen before include "Snatch" , "Rob" , "Creep" , "Shoplift" , "Take illegally" .)
