Delete duplicates

[mtpayami]

Hi all,
I've been using czkawka a little bit on a small number of folders and files. I have now launched a scan on duplicates files on big hard drive with important data.
I trust the software but I have a question which I couldn't find a clear answer for:
let's say that the scan has found couple of duplicates ( even 4,5 same files) , WHAT happens if I select all and delete?
Does , at least ONE file remain ? or will I need to uncheck one by one each set of files to be able to keep at least one of the files?
I don't want to use the move command as duplicates data found are enormous!
Thanks for your help!