It had been Obi-Wan who had held Anakin back before. Who had grounded him and talked sense into him when he was getting way too emotional to think clearly. staying back on Coruscant while his former teacher was sent away had left him to deal with everything that was piling up way over his head all by himself.

"When I arrived, Master Windu had the Chancellor pinned down. I saw an old man begging for his life and a Jedi Master raising his lightsaber to strike down the man that had been a close friend to me ever since I came to Coruscant." Anakin gave more detail to the event, yet didn't look at Obi-Wan "I knew that Palpatine was the Sith Lord. He had told me. I have seen him use his Force Lightning against Master Windu. I knew exactly whom I was saving..."

"I made a decision that costs the lives of countless Jedi. And all that after Master Windu himself told me he trusted me." That detail alone only made it worse. He had just finally gained the Jedi Master's trust, then went to betray him and everyone else.

"...if only it were possible to go back... To do things differently..."