Does anyone else find it odd that, after being stabbed multiple times and tumbling down a staircase, Arya was able to kill the Waif, a trained and experienced killer, by cutting a candle in half and fighting in the dark?

Like, Arya is used to being blind, but she was never able to defeat the Waif. There's no logical reason for her doing so while extremely injured.
Poor Lady Crane, though.
