A horse in the sand doesn't sound like "clip clop" as it's muffled... Sounds or so hard to translate in words ! but I guess it'd be more in the order of a "thump thump" ? One thing is sure : it's such an amazing sound *not useful at all*
Hmmm, her face seems less dubious in the "Oh, I am going to do something entirely stupid that will probably mortify you and I probably won't care" way than the last. To be honest, and please don't kill me as you may interpret it differently, it says "Oh, you are such as sad soul and I pity you greatly." It doesn't translate as well as it did with the prior page, where it was apparent that she would abuse the mask's power.
Of course, this is your comic and you are 100% free to do what you wish with it. Like I said, please don't kill me, oh GOD SPARE ME. I'd rather hear your reasons as to why you chose Vesper's expression over anything else. (To be honest, I am so used to critique or questions being equated with flaming that I comment with a disclaimer.)
But the flow of the page is much, much better (loving the whimsical boxes.) Can't wait to see your future changes.