After a season's worth of danger, last week's The Walking Dead left the characters as they prepared to enter what Rick guessed would be the safest place in Georgia: the CDC. At first, it looks like he may have been right; the survivors enjoy hot showers, a decent meal, tons of alcohol, and 100 percent fewer zombie encounters. Unfortunately, as "TS-19" proved, there is no "safest place in Georgia"&—and no way to tell where real danger will come from.
The group's new ally is Dr. Edwin Jenner (Noah Emmerich), introduced last week as he performed strange experiments in complete isolation. Last week's episode gave us a window into Jenner's despair ("I think tomorrow I'm going to blow my brains out") that the survivors don't have any context for, and a lot of this episode's tension comes from waiting for the group to ask Jenner the uncomfortable questions that only he can answer.
The only person who's not enjoying the relief of this newfound shelter is Shane, who begins to grill Jenner just as the survivors are enjoying themselves at a family-style dinner. "TS-19" opens with a flashback which reveals that Shane was telling the truth: he really did believe that Rick was dead when he decided to abandon him at the hospital. It's a shame to lose the compelling moral ambiguity that framed Shane's decision, but it helps to explain both his shame and his anger since Rick returned—he's recognizing that he abandoned and betrayed his best friend, but also knowing that he genuinely did what seemed right (even if Lori doesn't believe him).
So far, the zombie outbreak hasn't fundamentally changed Rick's character, but "TS-19" makes it abundantly clear that post-zombie Shane is antithetical to what he used to be, and getting worse. The Walking Dead can be a little on-the-nose at times (did we really need the shot of Shane swigging from a whiskey bottle in the shower?), but his drinking leads to a believable, ugly scene in which Shane aggressively attempts to rekindle his romantic past with Lori. When she tells him to stop, he doesn't, and it's not until she scratches him that he bitterly backs off. Zombies or no zombies, there's no safe haven for Lori as long as Shane's around.
Meanwhile, Rick, who's similarly drunk but far less violent, has a lucid conversation with Jenner. Rick has been unwaveringly hopeful and courageous around others this season, and it's telling that Jenner is the person to whom he finally voices his doubts. Though it's not immediately apparent, Rick and Jenner have a lot in common: complete devotion to their loved ones, and a soft spot for strangers in need (think of Rick's sympathy for the Vatos in episode 4, and how closely it echoes Jenner's sympathy for the survivors in the first half of this episode). It's even apparent in the way they dress. Like Rick, Jenner wears his uniform (in his case a tie and lab coat) despite the complete breakdown of conventional social structures. There's an important, symbolic message in keeping traditions alive, because those traditions affirm what makes us human. Rick and Jenner both understand that.