Can dual redundancy help with a disk failure during a rebuild?

Drobo - End of Sale Drobo S
1

When a drive fails, replacing it with a good disk triggers a rebuild process. I believe during the rebuild, any single disk failure will cause all data to be lost. With dual redundancy, I’m hoping that a single-disk failure during a rebuild will not result in total data lost. Can someone confirm the validity of these statements?

I would love too see this demo on a Drobo S with dual redundancy:

  1. remove a disk.
  2. replace disk with a blank one. rebuild should start.
  3. while rebuild is still in progress, remove another disk (not the blank one). check if data can still be accessed.
2

yes, your data is safe in that instance, that is the point of dual disk redundancy - you can survive a second disk failure during the rebuild from a single disk failure