'TS-19' was a fairly good season finale episode. When they arrive at the CDC, the group is spotted by a lone doctor still operating the facility - the doctor opens the door and survivors enter into the unknown.

Rick and Shane have it out about what the next best move is for their group, and after secretly pointing a gun at his best friend's back, guilt-ridden Shane concedes that the group should follow Rick to the CDC facility in Atlanta in hopes of finding rescue. Andrea is understandably traumatized, with only surrogate father-figure Dale (Jeffery DeMunn) there to comfort her. As the Merle search party returns to camp with a fresh supply of firearms, zombies attack, inflicting heavy casualties on the survivors, including Andrea's sister, Amy (Emma Bell), who Andrea is forced to put down when she rises as a zombie. The group doesn't find all of him, just the hand the hillbilly sawed off to escape. Merle's brother Daryl (Norman Reedus) isn't at all happy to hear his kin was abandoned, so Rick takes a group of men back into the city to find Merle. The happy reunion didn't last long: Rick's group was forced to leave a drug-crazed Merle behind in Atlanta, and little did Rick know, Lori and Shane had become lovers since Rick was presumed dead - an affair Lori is having trouble keeping under wraps. Rick made it out of Atlanta alive, only to find his wife, son, and best friend/cop partner Shane (Jon Bernthal) waiting at a survivors camp in the woods. Atlanta did not provide the salvation Rick hoped for instead he found a metropolis overrun by zombies and would've perished if not for the help of fellow survivors Glenn (Steven Yeun), Andrea (Lorie Holden), T-Dog (IronE Singleton) and the not-so-friendly Merle Dixon (Michael Rooker). After help from a kind stranger (Lennie James), Rick set off for Atlanta to find his wife Lori (Sarah Wayne Callies) and son Carl (Chandler Riggs). This season we've witnessed officer Rick Grimes (Andrew Lincoln) awaken from a coma after a shootout gone bad, only to find himself in the midst of a zombie apocalypse.

Rick the walking dead pointing gun