OKAY, here's my explanation of things.

Dreadwing never saw Breakdown get dismantled, he just heard his screams when Airachnid attacked him.

That being said, he doesn't actually know if Breakdown is really dead or not.

Skip ahead to M.E.C.H finding where Airachnid supposedly "killed" Breakdown. Instead of finding Breakdown's dismantled parts, they only find a disturbing amount of energon.

To sum it all up, no one actually knows if Breakdown survived the attack or not.

That's my theory for this fanfic because...

And...