Walter falls silent for a while, running different coding parameters in his mind now, and then checking in on the latest strangeness in the news now, and then double-checking his email now...

But he doesn't fail to notice Ben's question in the middle of that - and between the worry of this just being a symptom of regular stress, and the worry of this being a Numbered thing for the teen, Walter finds himself hoping it's the former.

"The shelf, behind you." With a select few other tools, and a handful of screws that had been left out for some reason.

There's no hiding the worry on Walter's face, either.