I'm only counting on-screen kills, and only when zombies kill humans or humans kill zombies.
Warning: Spoilers ahead if you haven't seen this episode yet!
Episode 4: "Vatos"
First off, I wasn't a big fan of this episode. There were some nice scenes, and they did a good job balancing between character development and zombie horror. But I was a little dismayed by the "gangbangers with hearts of gold" reveal, and they laid it on a little thick with Jim's "now I remember my dream" ending.
I like Redneck Daryl a little bit more every episode. Loved this exchange with Glenn:
Daryl: "You got some balls, for a Chinaman."
Glenn: "I'm Korean."
First kill this episode -- other than Amy and Andrea taking down a bunch of fish -- goes to Daryl, nailing one with his trusty crossbow inside the building, then we see One-Handed Merle had killed two on his way to the kitchen and his self-cauterization. Does this violate the on-screen kill rule? I don't think so... he was the only one who could have done it. What I meant by that was I don't want to give credit just because a guy says, "I killed fifty zombies." I want to see bodies. So let's give Merle those two.
During the scene when Glenn gets grabbed, you see one of the Vatos slash a zombie across the face with a knife or something, but it clearly didn't kill her -- you can even see the zombie trying to get up as they leave.
Then we get a lot of stand-offs and stare-downs, but no actual killings 'til we get back to camp and the big zombie attack starts. (I thought they'd show up a little earlier, with the tied-up Jim getting eaten to make everybody feel guilty.)
But finally the zombies show up and bag their first human, as Wifebeater Ed gets chewed up in his tent. Then they get the first of several bites of Amy (whose last words are, "We're out of toilet paper?")
Then Shane finally gets on the board, hitting four zombies with his police shotgun, and then we hear a fifth shot off screen. Five kills? Well, I'm sorry, Officer Shane, but those don't all look like headshots -- are you still aiming center of mass? We know all those zombies die eventually, but I'm not sure it was all his doing. Let's say he kills three with those five shots.
Gravedigger Jim shows he's good for something other than digging holes, putting a Louisville Slugger to good use on a zombie. There's a gunshot -- from Dale, I think? -- but you can't see if he hits anybody. The zombies bag another humie with a double-team. At first I thought it was Morales, but it was just some NPC, as in the very next scene Morales making like Gallagher on a zombie. Dale gets off another shot with his bolt-action rifle, but again, can't see the results. Let's say he went 1 for 2?
Jim takes out the zombie chowing down on Amy, then we hear four more gunshots (let's give one to Shane, one to Dale?). Cut to a zombie grabbing on a brunette hottie they'd somehow hidden away until now (guess she wasn't part of the laundry detail), then Morales again doing his A-Rod impression with his second kill of the night. Another mystery gunshot as we see a zombie eating who I guess must be Wifebeater Ed judging from his size. Morales nails another one. Shane fires two more shots, and once again, the second shot appears to hit a zombie in the stomach. Come on, Shane! That's just going to make 'em mad. Just to be nice, let's say the first shot was a kill. Two more shots soon follow, but you can't tell who pulls the trigger.
At this point Morales is standing by himself swinging away as everybody else backs toward the RV. Thought for sure he was going to eventually get mobbed and, Elias in Platoon style, get eaten as everyone else watches from the safety of the RV. He nails three with his baseball bat as Shane -- with a shotgun, remember? -- sticks with the women and children. Nice.
But Morales is saved by the timely arrival of Rick, Daryl, Glenn and T-Dog, who make good use of the bag of guns. Rick gets six -- five with the shotgun, one with the revolver. Daryl, wisely switching from crossbow to shotgun for this kind of crowd control, gets at least five. Glenn gets four. Give two to T-Dog (one he shots, another he appears to be bashing on the ground.) There's a few more zombies who get shot in the head and you hear a few more gunshots during Rick's reunion with Carl and Lori, but it's impossible to say who did the killing.
Obviously, it's a season-high for humans getting killed as we hadn't seen any bites up 'til now, but the 34 zombies killed also is a season record, beating Episode 2's 31.
By the way, someone's going to have to put down Amy, Wifebeater Ed and the two NPCs before they reanimate.
Humans Killed: 4
Zombies Killed: 34
Humans Killed: 4
Zombies Killed: 80
Season Leaderboard: Rick 39, Daryl 8, Morales 7, Glenn 6, Merle 6, Shane 5, Morgan 3, T-Dog 3, Jim 2, Dale 2