But instead, out of the blue, here comes a truck that just happens to have a load of steel pipes, turns in front of the guy, one pipe breaks loose and stabs him through the heart.

Ah-hah! Bad guy #3 also died from a stab wound through the heart. I didn't see that, even though I was looking right at it.

That does make sense, and would explain Dean's take on it being unexpected and out of the ordinary. Thanks!