10/20NL Problem

[Dk4884]

I limped with 86spades after 1 early pos. limper and the SB raises to 60, limper calls, so do I. Flop comes 10 7 2 w/ one spade. SB bets 100 into 187 pot and early pos limper calls as do you. Turn is 5 of spades, SB bets 400 and the early pos. limper folded (happen to be Mike the Mouth but not important). I called because at that point I felt alomst certain he had a big PP and I figured it's +EV because if I hit my hand it's a guaranteed double up and if I miss it doesnt leave me short stacked ( I had started the hand with 2300 and the call put me at 1500). What do you think? Bad call? Is it + or -EV move?