He wanted to go before the TRC to get his story on the record. Off the record, certain folks let him know that he was free to testify to absolutely anything that the previous government did. If he testified against the ANC, CPSA/SACP and especially Umkhonto we Sizwe, he might end up with his head cut off or otherwise severely punished. He fled SA shortly after that.
TRC's may not be as fair or useful as you might believe. Unless it's run by an independent third party and held to a high standard, it's going to end up being whatever the sponsoring government wants.