Walk through the hole you've revealed into the elevator shaft. Walk to the right wall, down toward the camera, and climb the ladder to the top. Become Gooigi, and walk to the far left corner of the landing. Ooze through the floor and you can collect the B1 blue gem.

Once inside the parking garage in B1, Luigi's Mansion 3 players should notice an idle car covered with a white sheet. Use the vacuum to pull the sheet off the car, and activate the button with a shine of the flashlight. The trunk should open, revealing the white gem.

With Gooigi, use the suction shot to open up the power box. After pulling the panel off the box, use the Stobulb to flash the green light. The electricity will power the machine and release a red gem.

Use your vacuum on the chandelier. While holding down ZR (as Luigi or Gooigi) switch to the other character and have them use their vacuum on the chandelier too. This will cause a yellow gem to drop from the chandelier.