Hello. I urge that since it appears you are seeking legal advice pertaining to security matters related to a medical doctor's office, you ought to contact a private attorney. Under certain circumstances, surreptitious videotaping of patients raises invasion of privacy legal concerns , as well as allegations pertaining to criminal conduct. The physician may have concerns about possible staff involvement. All the best.
Employers may install security systems including cameras, although there may be limitations in such installations if the person being recorded as a reasonable expectation of privacy (i.e. restroom or staff dressing area). Your question does not provide enough of a description as to who is installing the cameras, where they are being installed, etc. for an attorney to give you an answer in your circumstances. You should contact an attorney for a private legal opinion, after telling him or her all of the facts.
Nothing in this answer should be construed as legal advise and does not establish an attorney-client relationship without a signed legal services agreement