The Resident Evil 4 keycard can be upgraded to level 3 in the Remake to access the whole of the lab, but it's not easy to do when the Regeneradors are prowling the area and Ashley is being held prisoner nearby. This is definitely one of the tougher areas of the Resident Evil 4 Remake, especially considering that you won't be able to kill the Regeneradors for a while, making running about with the keycard as you try to upgrade it all the more challenging. Avoid them while you can, attacking them only to slow them down and avoid them, as they can recover from any attack until you get the Biosensor Scope later.
Clearly anybody here could using a helping hand, so here's a walkthrough to help you get the keycard in Resident Evil 4 and upgrade it to level 3.
How to get the Resident Evil 4 keycard in the Remake
The info on how to get a level 3 keycard is found in the same room as the Power control Lever. This lever is integral to getting the card, as you'll be using it to switch power between two areas to access the equipment you need.
For now flip the lever so that the right-hand side of the map on the display is lit up green. With the power redirected, go to Dissection by heading out the door and turning right, looking for a now powered computer terminal.
The code to the Dissection door involves rotating layers of junctions to reroute power to the two power nodes. To do that, move left and right to switch to different layers of the puzzle and press the button to rotate the junction symbols and connect the power lines. Here's the solution:
The Resident Evil 4 dissection room power puzzle solution
Once you have all the nodes lit up, move the switch all the way to the right to select the nodes and press the button to fix the circuit and open the door. The Level 1 keycard will be on a table at the back.
WARNING: once you have the Level 1 keycard a Regenerador will appear outside the room. You can't kill this enemy yet so just try and avoid it best you can.
Now you have the Level 1 keycard head back to the power switch and flip it to redirect the power and activate the level 1 lock you can find here:
Avoid the Regenerador as best you can and open up that door to the Freezer room. At the back you'll find a Keycard machine that will upgrade your keycard to level 2 but don't use it just yet as that will release another Regenerador. Instead, take a look at the Freezer Room door code puzzle sealing the nearby door. You can solve that using this solution:
Resident Evil 4 freezer room power code puzzle solution
Opening that up will earn you the LE 5, a submachine with piercing power to shoot through enemies. It's one of my favorite Resident Evil 4 weapons because it can hit everyone in a crowd, so it's worth picking up.
When you're ready, put the keycard in the machine and you'll see a progress bar filling up. A second Regenerador will appear so run away and avoid both until the card machine is ready.
Once you're able to get the Level 2 Keycard you can open up the Level 2 lock you can find here:
That will open up a new area with a level 3 door and a final overwrite terminal to give you a level 3 keycard. It's located in a back room, behind four Regenerators in glass tanks.
These enemies won't come out unless you break the glass, but unfortunately you're going to have to shoot at least one - the keycard overwrite machine is locked and Leon will mention you need the Resident Evil 4 wrench but it's inside one of the Regeneradors. Grab the Bioscope that's also in the room and attach it to whichever gun you have that will take it using the 'parts' option. Once it's attached to the gun, scope out the Regeneradors in the tanks and you should see the wrench:
You'll have to shoot the Regenerador to release it and then kill it to get the wrench. Once you do, use it on the keycard writer to upgrade to a Level 3 Keycard. Again, it will take a minute or two and this time you'll be attacked by some Ganados. If you're careful you can avoid releasing anymore Regeneradors but chances are, a melee attack or some dynamite will set at least one free. So be prepared to fight them.
Once you've killed everything and got the Level 3 keycard you're all done. You can finally reach and open the Level 3 door between you and Ashley and carry on with the game.
