Well, you can bleed out from any major wound in 20 minutes without a tourniquet! From what I read, (from other sources, too, wikipedia's just on my favorites list) he didn't think the wound was serious and bled to death because he didn't seek medical attention.

And it's true about soft armour, but it's still like taking a sledgehammer hit instead of a bullet going through you- that baseball's slowing down, but it's still making it through the plane of the sheet!