Worst PF fold ever

[soko]

4-8 live game

UTG live-straddles, $8 is the bet to call
UTG+1 Folds
UTG+2 raises to $12
Fold
MP+2 calls $12
MP+3 calls $12
Button calls $12
SB folds
BB calls $12
UTG raises to $16
UTG+2 caps at $20

Everybody puts their bets in, besides MP+2 who only throws in $4 instead of his $8 more he needs to call with, the dealer rakes in all the money to the pot and says, MP+2 you need to put in $4 more dollars.

MP+2 picks up his hand and looks at it, trying to figure out what to do, everybody is saying it's only $4 more, you have $16 in there already, and MP+2 mucks.