As I've never been able to watch DS on TV (except by DVD), and probably never will be able to as I highly doubt a UK channel is going to pick up a 40 year old American show (though the remake was on Scifi channel), I've only ever seen the end of the Adam storyline (aka. the episodes at the beginning of volume 11 DVD), and I find it really hard to watch and really bad. (And I prefer old TV shows to modern ones!) In this case, while I'd normally be annoyed by the lack of sendoff, I was quite happy with it as it meant that storyline was finally over and done with.
As an in context explanation... hmm. I'd prefer to think Stokes was keeping a black hole in that room.
I suspect that Stokes really sent Adam packing secretly - I mean, he wasn't exactly liked by other characters. So secretly that even the audience didn't get to see it!