Let me backtrack a bit and say, more accurately that "the ejecta aren't just tossed about due to recoil", both effects play a role. My point was that the flash

Let me backtrack a bit and say, more accurately that "the ejecta aren't just tossed about due to recoil", both effects play a role. My point was that the flash is caused by superheated/vaporized rock, which you will pretty much always get at such speeds due to the amount of energy released.