A few villians in this hand so i'll try to make it as clear as possible.
Hero (MP) has $180
Villian 1 (UTG +1) has around $60
Villian 2 (Button) has everyone covered, about $600
Villian 3 (BB) has about $200

Villian 1 opens to $3. This particular player has been opening pretty much any hand when he gets the chances and seems to be on tilt after getting sucked out on twice in a row. Hero looks down at A5o. I decide I'm going to try get this pot heads up with the raiser, as I should be plenty ahead of his range and want to play pots with him. Hero raises to $15. Villian 2 on button calls and Villian 3 on the Big Blind calls too. (Pot is $60~.

Flop is AT2r.

Checks to me and I decide to check. I didn't anticipate playing this pot 4-ways and decide to play a bit of pot control. The button snap bets to $50. Big blind looks very frustrated and tanks for a loooooooong time and eventually folds. UTG +1 folds and its on me. I can somewhat assume that the big blind had an ace judging by his long tank and the obvious tough decision he has. That would leave just one ace in the deck. The player on the button is a very competant and aggresive player, who does not shy away from a bluff. I have caught him in the same kind of spotting bluffing with King-High before, so I know it is not out of the realm of possibility. My hand is pretty under-repped and the board is extremely dry, so it does not make much sense to me as to why he would bet almost pot. If he had a premium like a set or two pair, he would most likely bet smaller into 4 people for value, as it the way this table has been playing it would be absolutely realistic to expect them to call with a 10 or a worse ace. In the end, the aggresiveness of the player, the fact my hand is under-repped and the very small amount of value hands he could have (keep in mind he didn't 4-bet me preflop) leads me to believe he is bluffing. I move all in and he snaps me off with AK.

My question is, how do I get away on the flop? I'm pretty sure I can't considering the action. Would love some feedback on this hand as I am stumped.

fold pre

fold flop now

villain called preflop (weighting his hand heavily towards pp's and strong aces) and bet pot into 3 people in a preflop raised pot knowing full well that the board hits PFR's ranges. just muck.

This is not the hand I want to try this with -- or the position.

Bet the flop yourself and fold when he raises or shutdown when he calls.

As played, just fold to his bet. I understand why you raised, but your hand just isn't strong enough and you do have showdown value, so I'd rather flat than raise -- although I still recommend folding.

A5 offsuit is a terrible hand make a 3-bet in middle position. Much rather want a hand like 76 suited.

You have to bet the flop. Sure, you're not sure if you have the best hand. But if you do, there's no reason to give a hand like KJ, QJ, or KQ a free shot to make a straight, or a middle pocket pair to make a set.

Bet $40 on the flop and fold to a raise, or shutdown if called unless you improve your hand on the turn. When you move in, it's a game theory disaster. You will fold out all worse hands, and, while you may get AJ or AQ to fold, no other hands will likely fold to your shove. The pot becomes $275 and V needs 135 to call, so he's getting about 2-1 pot odds.

Me, I just fold to the flop bet as played. If V has a strong hand, he's going to shove on you on most turn cards, and you have to anticipate that.

Betting this flop seems pretty crazy

First off, the A5o 3 bet vs EP in middle position isn't great. Your hand flops horribly when called (needs 3 low cards or to flop an ace, an ace isn't that good for you if you get action). You've still got several players to act behind you. Pitch it.

Flop check is good now that you got into this mess. I don't see why you think the big blind necessarily folded an ace, how many aces is he going to cold call a 3 bet with then fold the flop? He probably had QQ-JJ, maybe KK. When the guy on the button makes a PSB on this flop, I'm done. What bluffs does he even have here? KQs, KJs, QJs, if he's a little crazy, maaaaaybe. He has way more value with AK, AQ, ATs, TT, 22. Fold.

FWIW the other villian told me he had A7 but I see your point.

Yeah, something I've been trying to incorporate more into my game is more aggresive lines preflop. I think I got it wrong from the start as you said, A5o in MP is not the optimal play, and I got caught up worrying about V1 on tilt I forgot to realise 1. My hand isn't that good and 2. Half the table is still to act behind me. Once I made the first mistake, the hand kind of spiralled out of control and I was so blinded by my "reads" and all this other stuff that I wasn't thinking in the right direction. I"m obviously super frustrated to have punted off my stack like that, but I'm more frustrated that I let myself get to that point in the first place. I consider myself to be a pretty competant player for these stakes, and it seems pretty uncharacteristic of myself to punt like this. But I will learn from it, I hope this will help me in avoiding mistakes in the long run! Thanks for the feedback btw!

You can pick better hands to do this with, we got 3 callers which was not what we were going for which is a reason to slow down unless you smash the flop and then you missed the flop so I'd just let it go.

Generally we want to have branches of our decision tree when we stop putting money into the pot.