After last week, when Rick hacked off Hershel's zombie-bitten leg in view of five shocked inmates who have been presumably trapped in here since Day One, we pick right back up in the cafeteria one second later. Obviously the five once and present inmates and our heroes are pretty surprised to meet each other. One of the current residents draws a gun (the only one so armed; their arsenal is less Max Payne and more Clue) upon learning that Hershel's been bitten, but T-Dogg holds them at bay while Glenn ransacks the adjoining room they just stepped out of for medical supplies and Rick leads the effort to drag Hershel back out of there before he bleeds out. They make their way through a flimsily barricaded door and one helmeted walker courtesy of T-Dogg before they head back out, leaving behind five very confused dudes and half of Hershel's leg. This is not the rescue squad they've been waiting for.
The inmates decide to follow, brandishing their lame-ass weapons, while the invasion force returns to their cell block with T-Dogg and Daryl acting as rear guard. With Hershel down and laid out on the bunk in his cell, Carol takes over as the group's medical expert (we'll later find out that Hershel's been giving her lessons, so that she'll be useful during Lori's delivery), but Hershel's bleeding so quickly that it's not looking good. Oh, and there's also the thing where he's been BITTEN BY A ZOMBIE.
The inmates come out to the assembly room where Daryl is waiting for them, crossbow at the ready. Clearly nobody had to tell anyone that these guys weren't to be allowed into Cell Block C, where the group has set up housekeeping. Daryl tells them they've been pardoned and are free to go, not bothering to try to sound any more official than he looks, but the one with the gun doesn't seem as grateful for their freedom as the others are. Indeed, he's the only one who thinks it's odd that a bunch of people broke into a prison and aren't bringing a wounded friend to the hospital, which tells him that it's not any safer outside than in. A confrontation starts escalating with T-Dogg entering the room, so of course Rick has to go back and sort it out personally. But not without first urgently telling Glenn not to leave Hershel's side. "If he dies, you need to be there for that." I assume he doesn't mean in the emotional sense. Doing what needs to be done might prove challenging in Maggie's presence, but Glenn assures Rick that he's got it. Rick runs out to the other room, trustingly leaving the grate open for New Improved Carl to close and lock behind him without being asked, which he does.