Collaborator is configured such that once any defect has been found in any file of a review, then no files in that review can be removed. Your only option is to delete the review and make a new rev...
Not opposed to limiting who can remove files, or that a record be kept of that happening. (I think I have another ticket out there that it's not easy to see a 'log' of a review to see who did what).
But people do add wrong files, and even add wrong versions of files - which causes even more havoc. I'm tired of cancelling reviews and starting new ones because someone fat-fingered a file. (and tired of getting my own software engineers saying "how hard can it be to add this feature"... :-)