The best episode of the series so far. The storyline was very engaging and touching, I also liked how the episode continued to deal with Dan's personal life, especially around being able to care for his son. His wife is incredibly loyal and supportive although she's clearly having a hard time - very well done. And totally cool was the kid's reaction in the end. Yeah, if anyone would understand it's probably a seven-year-old.
I was very intrigued by the tachyon-guy showing up again. He was very enigmatic and I look forward to more to come.
All in all this episode sets a very high standard for the series, one which I certainly hope it can live up to.