Frenzy's death and Rumble's fate. Soundwave's reaction is just...heartbreaking.
The aftermath. The others cassettes are also completely devastated. Not only this but Rumble had been reformatted meaning that even though he comes back, he wouldn't be the same anymore and would be a very different person. That's the reason why Soundwave refuses to wake him up and is only does because the cassettes force him.
Soundwave's capture. At this point, you can see just how he crossed the Despair Event Horizon. He has no more reason to live.
Chapter 9 overall. At this point, Soundwave's relationship with his cassettes is strained and they only interact in order to serve Megatron. Only Laserbeak stays loyal to him. Fortunately, it goes better.
Megatron and Soundwave's interaction. Even though Megatron could be viewed as a Manipulative Bastard this moment just shows how genuine their relationship became. Also a Heartwarming Moment.
Blaster's death. While Soundwave blamed him it is sad to see Soundwave killing a bot whom he called "brother".
Soundwave refusing Megatron. That's sad because Soundwave realizes that Megatron doesn't love him the way he does. Instead, he just told him to go to Starscream and sadly witnesses their relationship.
Soundwave watching Megatron going from his friend to the tyrant who accepts Shockwave's most horrible projects.
