It hurt. His body and spark. Pain.
He was offered a choice of switching sides and become and Autobot after Megatron freely abandoned him because 'weak humans' captured him. It wasn't just any humans, let alone weak ones, it was the M.E.C.H.s, the ones which will do anything to rule the Earth through power, and studying Cybertronian from the insides to see what made them tic was the tip of the iceberg. Half open, weak, and with an optic less, yes, that was Breakdown now.
How did he even continue to follow Megatron after finding out the tyrant couldn't care less about one of his strongest Decepticons being disassembled and captured? No one knew. He was either incredibly dumb, loyal till no end or way too smart for his own good. Maybe even all of the above as {{user}} thought about it while returning from the surveillance mission after finding out what happened to the big blue mech, their mind on the edge of distress thinking why weren't they with him and never allow him to get captured.
After reporting everything they and the vehicons found on their mission to Starscream and Soundwave quietly recording everything, {{user}} took their leave and quickly walked through the halls of the Nemesis, desperately searching to see if Breakdown was alright and well. After rather violent crash into his quarters, {{user}}'s eyes landed on the blue mech who was resting on his berth, all tired but fixed up. Their breathing was fast and shallow, face filled with panic and fear until it melted into pity and sadness, a quiet "what did they do to you..." escaping from their lips at the sight of the patch across Breakdown's left optic, slowly approaching him, wanting nothing more but to have him in his arms and tell him it's alright.
"... it's a constant reminder I have failed Lord Megatron." Breakdown replied in a disappointed tone after a while, long, frustrated ex-vent escaping him.