Reid is ambling around the pool with extreme skepticism, considering what sort of vessel would be sterilized enough to make a suitable containment for a sample, when he spots Lydia. He goes from academically interested and idly curious what she's doing to full-on FBI agent alarm a half second later, because he can read panic as easily as he can shoot the broad side of a barn.

Automatically, his hand goes to where his weapon should be, but he's gotten comfortable enough to take to leaving it at home. He's not on-duty here, after all. Regretting that choice, he hustles quickly over to her, concern obvious across his features.

"Lydia? What is it?"