At first, Tarn goes to withdraw from conversation with Ratchet upon Megatron's cold look. That is until he mentions Sentinels Transformation cog being on the premises. He cocks his head and, of course, does the logical thing and begins to look more closely around the Medibay for where it could possibly be hidden- ignoring Ratchet's furious gaze in favor of beginning to wander around a bit.

"Hm, a shame about Pharma, really. But his death was his own doing." Tarn pauses,turning to look Ratchet in the face. "I certainly didn't kill him. In fact, those hands of yours are rather incriminating. Perhaps it was your doing."