Nothing Important Happened Today II (2001) is dedicated to the memory of Chad Keller, who was killed in the terrorist attacks of 11 September 2001. Chad Keller, a rocket scientist, was a family friend of Chris Carter and his wife, Dori.
Lucy Lawless was supposed to be a recurring guest in Season 9, but her high-risk pregnancy prevented her from returning.
The character of Shannon McMahon's listed birthplace is Snoqualmie Falls in Washington state, a location known for its appearance in Twin Peaks (1990).
Five days after this episode aired, Fox premiered the first episode of the new series that ultimately (and quickly) overtook The X-Files as their premier show - 24 (2001).
This is not the last time that Adam Baldwin portrayed the second-in-command of a Navy ship. He also played the XO in The Last Ship (2014).