This will never be included, or even slightly hinted to in the lore. Please don't make theories that a character has been abused in this way or anything of the like. /srs
There exists a very detailed and graphic description of Sidian Divinis torturing the former SN Leader Horrid_Night. Other than that, the asylum storyline focused on the torture of the doctor's patients/specimens.
Once again from the city guard lore, one of the guards fell off a bridge into a factory below, though it wasn't confirmed if their death was from the fall or factory.
Occasionally, a character may post media images that contain eye strain or flashing lights in the discord server but those images will have a spoiler over them.