"He's been exiled. Ratchet intervened before Megatron could execute him." The fact that he felt any kind of relief at Tarn's life being spared just sent him spiraling deeper into the mounting guilt.

"I should have been the one holding the sword." He was still playing the part of Megatron's hound when that was the last thing this young mech needed. "I should have killed him. Megatron's hands would be clean and Tarn would never have been a threat ever again."

Sixshot could still go out and do just that. He could leave this moment, track the scent and blow a hole clean through Tarn's head, quick and painless.