Nothing in this chapter shall prevent the immediate suspension without pay of any law-enforcement officer whose continued presence on the job is deemed to be a substantial and immediate threat to the welfare of his agency or the public, nor shall anything in this chapter prevent the suspension of a law-enforcement officer for refusing to obey a direct order issued in conformance with the agency’s written and disseminated regulations. In such a case, the law-enforcement officer shall, upon request, be afforded the rights provided for under this chapter within a reasonable amount of time set by the agency.