This is the final come-uppance scene for the hero (Richard Boone as Sam Moran) and the villain (Steve Ihnat as Kryder). Steve is responsible for the death of a young woman, and Moran intends to have revenge.
I know it's foolish to rail against the action of a TV show made 40 years ago (or indeed, of any TV show, since of course by definition it's on film and can't be fixed!) but I must say it's always annoying when the villain acts really stupidly, which is the only reason why they end up getting captured or killed in the end.
It happened to Steve Ihnat in The Blue Light, when he runs away from Robert Goulet even though he's got a perfectly serviceable knife, and it happens here, when instead of plunking Richard Boone with his spear gun, he tries to run away....only to be cut off by Boone and... well - you'll see.
I love Ihnat's vocal delivery in this, somewhat reminiscent of his vocal inflections in Mannix: Endgame... but how he could let Boone sneak up on him.... silly!