Force Closing Finder, Deleting Files, Recovering Said Files?
Ugh - Do you know specifically if you used Finder to move a folder within one volume or copy the contents to another volume?

If you were copying, boot to recovery and run Disk Utility or power off and run file recovery software like Data Rescue.

If you were moving, then finder can't have caused the issue - force quit or not. Look at backing things up immediately and checking the drive / Disk Utility or hardware test.

Also - you might want to be sure you have Journaling enabled on all the drives in question. That will save you hours of check time when things crash - you might lose a file, but the loss will be quick and then you can move to restore things from the cloud or the backup.