Here is another take on accessing the data on the corrupt Windows 8.1 BitLocker secured drive.
SystemResuceCd to boot the system from.
Rufus to create a bootable USB flash drive from an ISO file.
ddrescue to create a image of the deivce. I used an external USB drive so that when I was done with the image I could easily move the drive with the image to a working system.
Windows Disk Management to mount the VHD file as a drive.
You are prompted for the BitLocker password key.
Drive may require fixing. Mine did and it took a long time.