No access to NAS after hot swap

I had a drive failure. Backed the NAS up to a Seagate portable USB drive. Backup completed successfully. Like a goof, I didn’t remove the USB drive. Hot swapped the bad drive. Waited waited waited like 12 hours. Power light and new drive live both solid blue. Existing drive lights blinking blue. Used WD access to try to shut the drive down. Then used power switch. Now the message for about 36 hours is “system shutting down”.

Questions:

Can I yank the USB drive without data loss? Can I yank the NAS power without data loss?

Thanks for any help.