Nah, it's very hard to see something like blood with this kind of device. Anything that you see that is black in color is much, much cooler than everything else. The hotter something is, the more white it becomes. I assume you're asking about those black chunks you see flying everywhere? Those are pieces of debris, rocks and shrapnel, which were under the surface of the ground during the day, thus retaining no heat from the sun- so when it's suddenly blown out by a couple of bullets, it shows up as much cooler than the chunks blown off of the surface. You can see this in the weapons of the victims, too- see how they're all black? If they were fired a few times, they'd start getting brighter around the muzzle area. These guys didn't really get a chance to return much fire because like 8 of them were already shot before anyone realized they were under attack. Looked like the first shot was a clean headshot..