Hermione was just getting her bearings when she heard a strange sound coming from behind Harry. They were in a field, and there was most decidedly more noise going on than there would be if only two of them had just landed in the grass.
From her seated position, Hermione turned slightly, and was met with the sight of two sets of legs that appeared to be attached to nobody. Except they were moving around. And she recognized the shoes. She expected she'd recognize the bodies to which they belonged, too, were they not covered by Harry's Invisibility Cloak.
Aghast, her jaw dropped, and her head swiveled toward Harry so fast she could have broken her neck. "WHAT IN THE NAME OF ALL THAT IS DECENT HAVE YOU DONE, HARRY??" The fury in her voice was unmistakable; the two stowaways under the Cloak didn't need to see her face to know how ballistic she was about to go.