17. Except in so far as in any particular case any privilege or immunity is waived by the Director General of the Agency, an expert (other than a member of the staff of the Agency), in the exercise of his functions in connection with the Agency or in carrying out missions for the Agency, shall enjoy:—
(a)immunity from suit and legal process in respect of things done or omitted to be done by him in the exercise of his functions, except in the case of a motor traffic offence committed by him or in the case of damage caused by a motor vehicle belonging to or driven by him;
(b)the like inviolability for all his official papers and documents as is accorded to a diplomatic agent, to the extent that this is necessary for the exercise of his functions, including during journeys made in carrying out his functions and in the course of his missions.