As Steve says you would probably wreck your computer.

Every single modern computer on the planet has thousands of duplicate files. Most of them are necessary for various programs including the operating system to run. They are in different folders so each individual program can find and use them. If you allow a program to delete them you are begging for trouble.

Let us know what those specific dupes are and we can tell you whether it's safe or not. Unless they are in a temp directory odds are they have or at least had some use.

The only thing a duplicate file finding program should ever be used for is to search a storage drive/folder for duplicate media or document files. In particular jpegs or mp3's because when deleted they will not be missed.

There are plenty of other safe ways to create space on a full drive.