Cool spot. Against [AA] and basically any range for the BTN, sensible ones and only half-sensible ones alike, you have somewhere around 21% equity in a 3-way all-in pot. That HH format makes it tricky to figure out what the total rake would have been had you stacked off, but it looks like some rake has already been taken from the pot, and it should be a roughly neutral EV call.
Preflop: Hero is MP with 7 9 T 6
UTG folds, Hero raises to $0.50, CO calls $0.50, BTN raises to $2.35, 2 folds, Hero calls $1.85, CO raises to $9.75, BTN calls $7.40, Hero calls $7.40
Flop: ($29.60) 8 2 3 (3 players)
Hero checks, CO bets $16.72, BTN calls $15.25 and is all-in, Hero folds
Turn: ($60.10) 8 (2 players, 1 is all-in) River: ($60.10) K (2 players, 1 is all-in)
Results: $60.10 pot ($2 rake)
Final Board: 8 2 3 8 K
BTN showed 8 7 4 4 and lost (-$25 net)
Hero mucked 7 9 T 6 and lost (-$9.75 net)
CO showed 8 A 5 A and won $58.10 ($33.10 net)
against both its probably a close fold. We can pretty much guess our villains have aces and a set (obv not). Were relying on backdoor straight and flush and the flush may be no good depending on the Aces.
4:1 is all well and good, but we are way more likley to be crushed with the info we have at that point imo.