without a surgically embedded microchip of some sort there should be no problem...retina scans, fingerprint recognition...no big deal. Even facial recognition technology is not a violation....go to work or quit the job, don't expect the world to comply with your every need.
Once again, you need to know your Bible, and you also need to know how a biometric scanner works. The Bible talks about the Mark being a number "in the right hand or forehead". A biometric scanner does not actually compare the image of your fingerprint or retina with another image - it uses an algorithm to convert the image of the fingerprint into a number and compares it to what is on file.
I'm not saying I agree that a scanner is the Mark of the Beast, but considering the stakes, I cannot condemn this person for being cautious.