The title is from a quote from William Shakespeare's play "The Merchant of Venice" - "The quality of mercy is not strained, It droppeth as the gentle rain from heaven".
Robert Patrick later reprised his role as Major John Skokes in The Light Brigade (1996). That episode was the first sequel in the history of "The Outer Limits".
This is the first episode to take place on a celestial body other than Earth. While it is not made clear in this episode, the alien prison was later revealed to have been located on a small moon in the sequel The Light Brigade (1996).