The reactions are a bit mixed up, but I’d say it’s the reactions of Apple Bloom and Scootaloo. Sweetie Dumb has this ‘looking-forward’-expression that suits her, while also being completely oblivious to the dangers of such a trip. Now Apple Bloom’s ‘confident’ expression would be more suited for Scootaloo. After all, she is only capable of mimicking Rainbow Dash, so she would be looking forward to any threat, deanger or thrill. The ‘Oh-my-god-what-are-we-doing-let’s-get-out-of-here’-expression from Scootaloo would be more suited for the more reasonable Apple Bloom.