2 are already in the machine, and the other 3 batteries can be found around the building, they are fairly common. He will tell you there is not enough power to launch the rocket, you need 5 batteries to fix this issue. This will unlock a new discovery of a command you can teach 2-BIT.
To the left of the stage there is a button to manually activate the grinder. Ground Up: Updaam – Evening // In Dorsey Manor you can fall into a meat grinder below the stage where Eternalists are telling jokes.Get Blown Up: Possible with your own grenade.Succumb to Fatal Depressurization: The Complex – Afternoon // Getting spotted by a sensor in the Wenjie Lab area will trigger depressurization.Choke on Poison Gas: Karl's Bay // There is poison gas in Hangar 2 (which is where Harriet holds her speech).Fall: Fall from any height high enough to kill you.A good place is at the edge of Karl's Bay.