The thing I can't believe is that they keep driving toward the meteor, even when it looks like it's headed right for them. I have to say my immediate response would probably be to slam on the brakes.
I was thinking something similar. The Soviets were at times well regarded in the West for their civil defense preparations. But none of these Russians seem to know how to duck and cover.
Most likely a sonic shock wave, not an explosion. Even if the meteor broke up, that's very unlikely to be the source of the sound. It's more likely like a sonic boom you're hearing.
