The principle of the quarantine is to keep the files detected (in case they were necessary) while disactivate them.
You can then keep them in the quarantine for a time, and if disactivating (putting them in quarantine) them don't create any issue, you can choose to delete them from the quarantine.
You can also choose to use the AdwCleaner function to uninstall it :
- It will delete the quarantine folder.
- And delete the executable.
And that's all because AdwCleaner is just an executable, it doesn't have a real install, and then don't have a real uninstall.
Hope that will help,