Cannon perform split edit with multicam clips? 'Break apart clip items' is greyed out...

I cannot perform a simple split edit with a multicam clip. 'Break apart clip items' is greyed out. I want to disable the video and have another clip play over the audio portion of the multicam clip. Am I missing something?

How do you perform a split edit with a multicam clip?
Any advice would be greatly appreciated.

Thanks in advance.