OK, let me say a couple things here as a serving Army officer:
-from what I've read in news reports, there were some serious screw-ups in the engagement that allowed these two soldiers (101st Air Assault Division) to get captured. Somehow, three troops (the two who were captured and murdered and another who was killed in the initial engagement) in a Humvee were separated from the rest of their unit. This should not have happened. Generally the minimum grouping is at least two vehicles and at least 6 troops.
One account I read said that there were 3 vehicles and 9 troops manning the checkpoint. The terrorists attacked the checkpoint and retreated, luring 6 of the troops to give chase in two of the vehicles. The remaining three either stayed under orders or didn't get underway before they were attacked by a second group of terrorists.
If this story is true, it was a fairly well planned and executed attack on the terrorists part. On the flip side, it speaks to poor decision-making and execution on the part of our guys' squad leader, added to the fact that they had probably fallen into a pattern in how they responded to attacks on their checkpoints, which may have allowed the terrorists to plan and carry out their attack.
-Next, every soldier I've talked to who has been over there has been unanimous on the point that there is no way, short of physical incapacitation, that they would ever allow themselves to be captured, because you know how it's going to end. Keep firing until you're out of ammo, and then fix bayonets and/or use your rifle as a club. Dead fighting is better than getting your head sawed off on video.
I don't know exactly what happened with these soldiers, but I can only hope they were unconscious, if not mortally wounded, before the terrorists got them.
God's grace to them and their families, and His justice to their murderers.