If Karkat and Katniss's mood patterns were made into a chart, as his measure of general contentedness tentatively rose, Katniss's is steadily falling. She's nothing near to a crying wreck, at least in her own way, but her discomfort with life has other ways of manifesting. Mostly in terms of her avoiding others in favor of shooting arrows at more things than is strictly necessary.

Normally when Karkat appears in the training center around the same time as her, she'll take a break to offer to work together or something like that - or at least say hi before continuing. This time, she seems more intent on shooting arrow after arrow into the exact same spot on one of the targets, to the point that it looks like it it's going to crack even it's superhero level durable exterior in half.

What exactly she's imagining she's shooting at is unclear.