Quarantine Queries

Can someone clarify some quarantine functions please?

Are files actually moved to the quarantine folder? Since the user cannot see the contents of the Quarantine folder this difficult to verify.
Sometimes I suspect filles are often still in their original location, but seem to be protected, eg cannot delete. So maybe Quaratine leaves the files in their original location and locks them up so they cannot do any harm?
Which is it?

EG my Quarantine has many entries for E:\autorun.inf, yet the file E:\autorun.inf exists. If I Click it, I immediately get a virus notification, I quaratnine it again, but the file is still there. Any attempt to do anything with the file, including deleteing it, gives Access denied.
If I select the file in Quarantiine, and choose delete, the file still shows in the file system.
What’s going on?

If I delete a quarantined item is it physically deleted and wiped / shredded?

Assuming files are shredded, is it possible to use the comodo shredding function to shred any other file of my choice?

I tried for you with CIS 3.13 and cannot confirm this behaviour. Consider a clean install and use this clean up tool after uninstalling to make sure you start clean.