With the loss of his champion, Tyrion was declared guilty and placed in a Black Cell in the third sublevel of dungeons in Maegor's holdfast (where Ned Stark had been kept). However, late on the first night of this captivity, Tyrion was secretly freed from his prison cell by his brother Jaime and a reluctant Varys. During their escape, when Tyrion thanked Jaime, Jaime revealed that he had owed this to Tyrion. In his explanation, Jaime recalled that their father had made him lie about Tysha being a prostitute, and that she was exactly what she seemed: a crofter's daughter who had genuinely loved Tyrion. Jaime suggested that Tywin rationalized this brutality and deception by saying that Tysha was so poor and to wed a Lannister was tantamount to whoring herself for the family's wealth. This news devastated Tyrion unlike any insult or act of aggression he had suffered at his family's hands. Tyrion abandoned Jaime, promising retribution if they ever met again. To hurt Jaime, he also revealed that Cersei was "a lying whore" who was "****ing Lancel, Osmund Kettleblack, and Moon Boy for all I know," and (falsely) claimed that he had indeed poisoned Joffrey. This shocked Jaime and may have lead to the first significant doubts and feelings of contempt that Jaime eventually began to feel for Cersei (as evident in A Feat for Crows). Before leaving the castle, Tyrion visited his father's room via the secret tunnels and, to his horror, found Shae naked and alone in his father's bed, wearing his chain of the office of the Hand around her neck. When Tyrion confronted her, she begged his forgiveness for betraying and humiliating him at the trial. But Tyrion, full of hatred, strangled her (with the Hand's chain) nonetheless. He then set out to look for his father. Before leaving the bedchambers, Tyrion took a crossbow from the wall and loaded it. He found his father sitting on the privy and confronted him (aiming the crossbow at him), demanding that he tell him what became of Tysha, his wife and love. Tywin asserted that he had not killed her but sent her away with her earnings. Tywin referred to her repeatedly as a "whore", leading Tyrion to warn his father that his next use of that word would mean his death (even then Tywin would not take his son seriously, saying "You do not possess the courage"). After Tyrion's repeated efforts to learn Tysha's whereabouts, Tywin said dismissively that she had gone "Wherever whores go." With that Tyrion fired at his father's chest just as he began to stand from the privy, and the bolt stuck him in the bowels. With his last words, he disowned Tyrion as his son. Tyrion escaped the way he had come, to a ship that awaited him on the river, which Varys had prepared for him.
Tyrion has since fled across the narrow sea, his motives unknown even to himself. In an excerpt from A Dance with Dragons on Martin's website it is revealed that Tyrion is currently in Pentos and is staying with Illyrio Mopatis. In this excerpt, Tyrion somewhat rhetorically asks several characters: "Where do whores go?" It is implied that his thoughts are still with Tysha, as his question appears to relate to his father's final explanation of her whereabouts.