I really admire the right tone's of artwork as well as the right amount of emotion an artists put's into their artwork. You did exceptionally well for both.
The perfect amount of detail was put into this. It really shows how much work and effort was implemented here. The detail on Scootaloo and her helplessness as she drowns in cold dark icy waters, the sheer emotion on Rainbow Dash's face as she speeds down towards Scootaloo's body. It really defines her character here and it shows greatly. It's the real eye catcher here and it impacts the audience greatly.
Everything else like anatomy is also fine and well executed too. The way you drew these two looks like an accurate portrayal of how they look on the show but there is evidence of your own style and in short; I love it!