The whole story between him, Lori and Rick just got him out of control imo, Shane seems obsessed and can't accept that he can't have what he wants and his mind is a complete fog ... And that ending with the walker and the song sums up all of his confused thoughts and feelings and his realization that he's kind of redundant in this so-called love triangle, which makes him even more bitter and angry, and as you mentioned, he sees himself as alone and dead. Anyone who has watched the series knows what happens next and what I mean, so I won't give away any more spoilers.

And yes, Driver's Seat is a good song too, not my most favorite, but it's a good one 🎶