I don't know what the driver of the intruding car was thinking; alcohol was a contributing factor, but the rest... who knows? If this driver had not been stopped, we don't even want to imagine what sort of damage would have been done if she managed to plow into crowds of runners.
Civilization is a fragile thing, and technology is often far too much of a force multiplier when someone just goes ballistic. As our society has lost its penchant for self-control, these events become more and more frequent.
Sad, but true, commentary!