Now I don't want to get off on a rant here but...
OK, I can't seem to find where the original discussion thread for this is so I'll post it here.
There has been some confusion/discussion/controversy regarding the 2 Crichtons and which is the "real" one and will one go crazy. Well, I just watched this ep again (thanks to the 23-hour Chain Reaction) and I paid attention when the baddy talks about the twinning process and why his PK slaves are crazy. He tells D'Argo that after about 30 or 40 twinnings they aren't good conversationalists. That's why they are all crazy, they've been twinned too much. If that is true (and we don't have any reason to believe it isn't) then the 2 Johns WON'T go crazy because they've only been twinned 1 time. Also, he makes a big point (even at the very end) that they are EXACT duplicates of each other. They've been "twinned". They are in every way the same person. No differences (other than their later experiences).
Hope that clears this up.
Later Scapers...!!!