Suppose Soundwave goes somewhere, ejects all of his cassettes, and leaves. (It doesn't matter where he leaves them, as long as the circumstances are such that the cassettes all find his behavior perfectly reasonable.)
When Soundwave returns, all of the cassettes are still there. Megatron arrives at the same time, but coming from the opposite direction.
Speaking at the exact same time, Soundwave orders the cassettes to destroy Megatron and Megatron orders the cassettes to destroy Soundwave. (Neither Megatron nor Soundwave explains the reason for such a command, so i won't bother suggesting an explanation here.)
Who immediately attacks Megatron?
Who eventually attacks Megatron?
Who defends Megatron?
Who immediately attacks Soundwave?
Who eventually attacks Soundwave?
Who defends Soundwave?
Who pauses to ask why Megatron and Soundwave want each other dead?
Who hesitates before doing anything?
Who doesn't do anything?
Who survives? Note that there is no reason why Megatron and Soundwave must rely exclusively on the cassettes for attack OR defense.
(Result: The Autoscout
slaughters them all.)
Just kidding. Seriously, though, what would happen in a fight like this?