The travel velocity of these two wave types is not the same (P-waves are faster than S-waves). Thus, if there is an earthquake somewhere, the first waves that arrive are P-waves. In essence, the gap in P-wave and S-wave arrival gives a first estimate of the distance to the earthquake.
With the mysterious U.S. Senator Eddie Morra (Bradley Cooper) providing him with a second drug to counteract NZT's deadly side effects, Brian uses his enhanced abilities to help FBI agent Rebecca Harris (Jennifer Carpenter).
Robin Williams (Mork), Pam Dawber (Mindy McConnell), Conrad Janis (Fred McConnell) and Ralph James (Orson) all reprised their roles and Shavar Ross voiced Eugene. Laverne, Shirley and Fonzie did not appear in the Mork & Mindy segments, though Mork mentioned Fonzie being a TV character in one episode.