Which part was the biggest mistake?
Limping in with Ac5c w/ 20 BBs?
Calling 4x BB raise w/ only 20 BBs?
Jamming middle pair into PFR and no redraws?
LOL.
My exact thoughts.
If you are going to build a limping range in this spot off 20bb, it should be with a linear range of
hands. That is, very strong hands such as AQ+/TT+ and hands that play well postflop and you can defend against a non-allin raise with, such as 98s, T8s, J9s, 87s. Regardless, having any type of limping range here requires specific table dynamics and the blinds need to be attacking limps at a high frequency. A hand such as A5s which isn't good enough to r/c or l/c plays better as a 2-2.5x raise here.
No clue what you're trying to accomplish by 2x pot shoving the flop, are you merging to look weak and induce a call from AQ/AK or something lol? Wishful thinking if so as A5 doesn't need a lot of protection vs your opponent's checking range and is never getting called by worse. Going 2x pot here is awful with any hand.