With all due respect, this is an examination that you are appearing for and your attire needs to be as simple as possible and you need to follow all the set guidelines. There might be thousands of Candidates appearing for the exam at your Designated centre along with you. The invigilators wont spare time for every Candidate to make sure they clear the security check. Let's say if you go with longer nails, the thumb impression wont match the one in the Application form. They wont wait until your thumb impressions matches. They ask you to move aside and move on to the next Candidate. Either your turn might come last or might not come again for security check. And you lose the opportunity to appear for the exam. There are no lockers available as well that you can keep your pouch or wallet or water bottle or hand bag or any metal jewelry that you decide to wear on that day. So they are your responsibility and you are not allowed to carry them inside either. So you have to choose between your belongings or keeping or cutting your long nails or appearing for the exam.