Rene Auberjonois (Alar) is one of many previous Star Trek actors to appear on Stargate SG-1 (1997). Other notable crossover actors include Marina Sirtis, Robert Picardo, Armin Shimerman, John Billingsley, Jolene Blalock, Ronny Cox, John de Lancie, Wallace Shawn, Tony Todd, Dwight Schultz, Robert Foxworth, Obi Ndefo, Gwynyth Walsh, and Rick Worthy.
The underground base they get into is a redress of the Stargate Command set. The angled braces on the side walls are the same as in the SGC.