One of the more impressive shots from the battle wasn’t the CG dragon or even witnessing the scorpion — the giant dragon-slaying crossbow — in action thanks to Bronn (Jerome Flynn). It was when the Dothraki hordes descended upon the Lannister troops and, right before they clashed in hand-to-hand combat, the Dothraki stood up on their saddles to fluidly shoot arrows at their foes. Episode director Matt Shakman explained in the after-episode special that on set “horse master” Camilla Naprous wanted to bring something no one had ever seen before.
Part of course:
All the details behind that 'Game of Thrones' insane dragon assault in 'The Loot Train Attack' (LATimes)