“A Human Reaction” is episode sixteen of season one of Farscape.
Moya comes across a wormhole and, through the other end of it, Crichton can see Earth. So he gets in his craft and enters the wormhole, hoping it will take him home. He seems to crash in Australia, but gets tranquillised shortly after landing – by someone he knows.
It seems that at least some people think he’s either an alien, or a threat, as the wormhole he went through is still in existence, and poses a threat to the planet.
It’s pretty obvious that Crichton is either going to go back through the wormhole somehow, or this is purely happening in his mind. Given what is going on, the latter seems more likely.