Resident Evil 2 Remake (2019) - Laboratory / Lab Puzzle Solution in Greenhouse Control Room & Herbicide Cartridge Synthesis in Drug Testing Lab. This guide has all possible solutions for 1st and 2nd playthrough, Leon & Claire.

In first & second playthrough the solutions will be different.

For the code terminal in the Control Room, imagine the blue alien letters were numbers on a keypad or phone. After entering both codes the Drug Testing Lab will be fully unlocked and you can use the machine there to synthesize the Herbicide.

LAB CODES:
3123 & 2067
2048 & 5831 (B Scenario)

HERBICIDE SYNTHESIS:
Solution A-Scenario: Red, Green, Blue, Red, Green, Blue, Red, Green
Solution B-Scenario: Blue, Red, Green, Red, Blue, Red, Blue, Green, Blue, Red, Green

*Green = Left, Red = Middle, Blue = Right

After this you just need to cool the Herbicide in the Low-Temp Lab in the basement (enter via Ladder in Greenhouse). You'll notice the door to the Low Temp lab doesn't open. Follow the area all the way to the end and you'll find a Signal Modulator (on 2nd playthrough the signal modulator is where you activate the bridge immediately after getting the general staff keyband). Take the Signal Modulator to the switchbox in the dark hallway before Low Temp Lab. You can see 3 letters on the switchbox. Examine the Signal Modulator and switch to the 3 letter frequency, then fine tune with the left and right stick until everything lines up. Now just put the signal modulator in the switch box and the power will turn on. Now you can enter the Low Temp Lab and cool the Herbicide. Afterward, return to the Greenhouse Control Room to disperse the Herbicide.