From the pics the light looks like something on fire. I'd speculate what he observed was a flaming oil slick on the water surface after the detonation. Also if

From the pics the light looks like something on fire. I'd speculate what he observed was a flaming oil slick on the water surface after the detonation. Also if that's true it means that they lied about it being "in the range complex" - looks like it almost made its way to Russia.. explains why they detonated it.. nice little engineer/QA conspiracy theory