I don't know what will happen if you try to remove the array, but Microsoft says:
Once you remove a mirror from a mirrored volume, the removed mirror
becomes unallocated space and the remaining mirror becomes a simple
volume that is no longer fault tolerant. All of the data on the
removed mirror is deleted.
Besides, if you leave the disks in an inconsistent state, one disk will be different than the other (corrupt). Best to wait until they are synchronized before you do anything.
You are supposed to wait until the disks are consistent and then select Break Mirrored Volume to create two separate disks/volumes that are identical (because the disks are consistent!).