The companions confront the Theorist with force, warning and memory. Each attempt ends before it can become a contest. He attacks language, muscle, certainty and recollection, then erases enough of the encounter to make the next approach feel new. An enemy who can edit the reason for resistance does not need walls around a prison.
Vraska carries a horseshoe from Jace's childhood horse Pewter, sent by Ranna as proof that a cherished illusion can still hold truth. The gift reaches him only briefly. He reveals that rebuilding himself and creating Tam cost pieces of his soul, yet the dominant self has discarded the very memory that could explain why she mattered.
Tam finds the injured group and repairs the psychic damage she can reach. She rejects another direct attack and points instead toward the tower's memory prisons. If the Theorist became unbeatable by cutting away the rest of Jace, then gathering those exiled selves can turn his method against him. Vraska recognises the unspoken ending: Jace designed a path that may require his body to die.