Mary didn't have time to fully read or even comprehend the material, instead, she was forced to create a flesh "pocket" in her midsection and store the materials there. It would limit some of the shapes she could take for the moment, since she'd have to have enough mass to maintain that

When the water started pouring in, she reached down and scooped up a handful, tasting it. She was susceptible to poisons, to a certain extent, of course, but she needed to take the risk here...

Fresh water. Okay. So that told her what kinds of shapes she could take if she had to. For now, she settled for forming a set of gills, forming a membrane over her eyes, and webbing her hands.