In the secure beverageer lab beneath the World of Refreshment, near Rex Meacham's skeletal remains, on a table. The location is accessible after restoring the park's main power in the quest Power Play or after Open Season. The lab can also be accessed without restoring power through the employee tunnels in Kiddie Kingdom, by walking through a pipe in the contaminated water supply room.
It's finally complete. Despite the treason and cowardice from my fellow Beverageers, I've finally completed the stable weaponization of Quantum.
I've triggered the military notification switch so it's only a matter of time now. Haven't been feeling well since going into the reactor after Bennell. Think I'm going to just rest here till my extraction team arrives.