JMM, it was more thinking out loud but to expand on this. In an emergency situation regular LE does have to comply with the regular routine such as Miranda before interviewing and or search warrants. This usually involves situations where there is an immediate threat to life. Example would be kidnapping and you have a suspect who has time sensitive information.

Expanded to a Terrorist would be something like expanded detention say 7 days because the information he/she may have could effect not just one life but conceivably thousands. The Standard would be reduced to reasonable suspicion as opposed to having to establish probable cause. At the end of 7 days either you have probable cause to file formal arrest charges or they walk.