Case 3 is a cutscene, as is Case 4-1. Before beginning Case 4-2, Girl Hunting, I'm going to address the unfinished scoop, Above the Law over at Wonderland Plaza.
Keep right upon entering Wonderland Plaza from the Food Court. If the timing of your game is anything like mine, you'll be met with the screams of Nick and Sally, hanging from the giant Willamette bunny.
Be sure to snap a picture of the drama for big points.
Plunge in and start slaying some zombies. Of course any Queens you come across will be very handy in clearing the area under Sally and Nick.
Once the area is clear of zombies, pick up a Hunk of Meat and toss it at Nick or Sally. (Right trigger to aim, X to throw.)
Nick and Sally will be knocked down by an accurate shot, allowing you to convince them to join you. Give Nick a weapon - Sally just wants to hold your hand.
Get Nick and Sally to follow you up these nearby stairs.
On the right is your objective for Above the Law, the "Lovely Fashion House."
Step inside to trigger the cutscene. Officer Jo is holding four young women captive in the store. Can't imagine why.
Sticking around inside the store is only recommended if you have the Small Chainsaw or the Hatchet. Otherwise, head outside the store and clear the area of zombies before sniping Jo, Cletus style.
The downside to the Sniper Rifle is that it's slow, and Jo will start killing the hostages. So (as with every major fight since Adam) your best bet is the Small Chainsaw. A couple swipes is all it takes to quickly bring down Jo.
Once Jo is defeated, you earn 30,000 PP and receive the handcuff key to free the four girls. With Nick and Sally, that's a total of six escorts.
Complicating matters is the fact that these four girls are the dumbest escorts of the game. Just getting them down the stairs is a challenge. I recommend clearing any zombies from around the base of the stairs and setting a waypoint there, then actually pushing the girls down the stairs one at a time.
Once everyone is finally downstairs, clear a path to Greg's Paradise Plaza shortcut.
Yippee - party in the ladies room! Once everyone is in position, use the mirror to jump to Paradise Plaza.
Here I have them in the Paradise Plaza bathroom, lined up double file, grade school lavatory style.
A combination of mother-hen-like adult supervision, judicial placement of waypoints and a deadly zombie slicer will get your crew through Paradise Plaza.
Here we are at the warehouse door -- note that I've set it as a waypoint. It helps to clear out the area around your waypoint so that the faster escorts are safe while you assist stragglers.
Get all six through the warehouse and back to the Security Office for a hefty 240,000 PP.
Before heading over to Seon's grocery store to trigger the cutscene that begins Case 4-2, Girl Hunting, I recommend you stop by the Huntin' Shack and pick up a couple fresh shotguns.
You can just make out Isabela's motorcycle near the front of the grocery in this shot. As you approach, the short opening cutscene is triggered and Isabela pursues you on her bike.
I've found this conveniently-nearby store, Rippers' Blades, to provide excellent cover.
Clear out any zombies inside then position yourself in the doorway, shotgun at the ready. Isabela will perform donuts right in front of the store.
Hold down the right trigger to make targeting easier.
Isabela will periodically drive off, and I suggest exiting the store to lure her back into position. Just be quick about getting back inside Rippers' Blades. I was a bit too slow here and Isabela flattened me with her bike.
Deplete Isabela's health and be treated to this victory cutscene. Rest assured you haven't killed her.
This completes Case 4. Case 5 begins at midnight at Nort Plaza.