With reference to the original question. I can't really imagine why you would wish to do that. Ie taxi as a student with a non flying friend other than to say .. Look I can taxi a plane. I would say a risk that it would be a chance to 'show off' and may lead to problems. Why not wait til legally able to take flying.
Much more enjoyable
Taxiing not without risks. A brake failure can be total sudden and rather surprising. It's happened to me. You might get caught out if in a tight taxiway and with no way out.
Rvr 800. What an incredible story. I read the event with fascination and much respect to the final outcome. Whilst we are not flying such powerful craft it rather nicely makes the point that ground ops may not be totally safe and risk free. I am most grateful for your posting.