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