Funny, I actually caught the latest episode when it initially aired, and watched it three more times, but nothing too pressing strikes me to write about. I'll definitely go back and vivisect it, but this episode struck me the same way "End Times" did (though, I felt that 4x12 had a lot more thematic fat and succulent stylistic gristle; but that's just a personal taste), in that it seems best to truly hunt for clues after the next episode at least.
Don't get things mixed up, even if there was something about "Rabid Dog" that didn't strike me as fully in line with the show's current atmosphere and style (long time writer Sam Caitlin took the directors helm for the first time, and his unique viewpoint shows...perhaps a bit too strong), this is a crucial episode. The final chance for a bloodless conclusion (...and really, despite knowing that horrible things will happen, likely to characters we've cared about more consistently than Walt; we still all somehow hoped there could be a resolution between Jesse and Walter) was averted, simply because Jesse had internalized the paranoid delusions of his teacher, and projected his fear of the boogey-man, when really Walt was preparing to cleanse himself completely of sin, with his surrogate son (and the DEA) being witness to his ultimate confessions.
What this episode encapsulates for me is the stylistic theme that the show has been cranking; the symbolic and literally shadow that Walt has cast over all those he claimed to be protecting, aside for the numerous others he has indirectly devastated (keep in mind all those tweaked and suffering cats from the Czech Republic that the viewer isn't even privy too). Even character has been filmed in stark chiaroscuro lighting, accentuating the dark parts of their being that have been exposed by the "light" of Mr. White.
Primary Tao: In which the show's universe becomes a perverse analogy to that trippy scene in Being John Mallcovich, where Malkovich enters his own head, and sees crowds of people with his head superimposed onto their; Walter White's world has become a phantasmagoria of his own decayed soul. Like that part in Inception where foot-soldiers of the minds subconscious would attack threats inside someone's dream.