There is an excellent explanation for what Nathan is doing in panel two. Hopefully most of you know what he's doing (shaking the water off).

So apparently people are capable of becoming so depressed they lose their soul. Yeah. I did that. Plus I wanted to add the poking joke in again. Poking is a running joke for me (and one of my friends; you know who you are).

Anyway, losing your soul, even temporarily, can make you do demented things like cutting down a stop-sign with an electric pizza-slicer (which I'm pretty sure is illegal, even if you somehow are able to pull off as amazing a feat as using a pizza-slicer to cut it down).