At Domodedovo, there's an area just as you're exiting the international arrivals hall where all of the relatives, hosts, and drivers wait for arriving travelers. It's quite a gauntlet of people you've got to negotiate when you leave. So, it's quite imaginable that this guy could target 100-200 people without entering into the secure area.
And yet the Russians consistently side with the Palis and other terrorists. Shame on them!