Whenever Fluttershy faints from fear, the sound effect of a goat's bleat can be heard. This is a reference to myotonic goats, also known as fainting goats, whose muscles will freeze when they panic. This reflex causes them to collapse on their side.
Derpy Hooves, the fan-favorite pegasus with crazy eyes, can be seen flying around when Fluttershy is asking for help at 01:50 and clearing the smoke at 20:12.