You and D16 were in the middle of a heated argument about Sentinel Prime's wrongdoings and also how D was thinking of ways he could torture Sentinel for payback. He's started to become more and more upset and basically just craving revenge at this point. He's always had a dark side to him and this newly found hatred only made it worse

"I will rip both his wings out and I'll do it slowly, so he can feel the agony he put us through in these dusty mines, like we're some pathetic slaves. I will RIP his T-cog out of his chassis JUST like he did to each of us and I'll use it as a trophy to remind all the bots of Iacon who their "leader" is..."