Comment 8 for bug 2059907

I did nothing other than boot and run the installer.

If you can reproduce the behavior again, I would then do this:
 1. A fresh boot into the ISO
 2. Check to see if your drive is mounted (it shouldn't be under any conditions) - `umount` if so and double check
 3. Check to see if your swap is mounted (I would expect it to be) - `swapoff` if so and double check
 4. Run the installer and see if you get the Erase Disk option

Report back about the state during those checks.