Andrew Polk has played five different roles over the course of the series:
- Episode 20.18 Brazil (2010) - Eli Driscoll
- Episode 18.16 Strike (2008) - Bank Manager
- Episode 13.12 Under God (2003) - Jared Sterling
- Episode 11.3 Dissonance (2000) - Stuart
- Episode 7.19 Double Down (1997) - CSU Technician
Mark Nelson has played four different roles over the course of the series:
- Episode 20.18 Brazil (2010) - Symposium Organizer
- Episode 15.6 Cut (2004) - Dr. Stuart Barton
- Episode 10.22 High & Low (2000) - Julius Reinhard
- Episode 6.14 Custody (1996) - Stein
Elizabeth Rich (Paramedic Larson) previously played the role of a woman in the gallery in episode 18.16, Strike (2008).