The lab.
The droid injected the entire black serum through the left pupil of Rufus. His black pupil shrank to the size of a point as the serum liquid covered the inner lens.
"ARGHHHHH!"
Rufus' blood-wrenching scream pierced throughout the lab. His optical nerves ruptured while the lens cracked like the surface of a mirror.
Slowly, the left sclera was covered with black threads. Much to his horror, his pain receptors turned more sensitive.
He continued to scream and wail with saliva dripping around.
[[Please don't disturb your companions by shouting.]]
The droid gripped Rufus' chin and pressed it up to shut his mouth tight. During the moment of pain, it was a natural response to scream to relieve oneself. This was an innate desire which helped in relaxation to some extent, but now even that right was denied to him.
His face muscles tensed further unable to handle the boiling stress inside. All he could do was let the pain torture him from within.