Regarding the communication Stones:
These were first brought up in Season 10 of SG-1. Daniel and Vala accidently used them to zap themselves to the galaxy the Ori were in, whereupon it was discovered that they had taken over the bodies of two people that lived there.
The stones work thusly (as I recall, this could be wrong infor, so you have bee warned): There has to be two stones for it to work, one on each end. The person initatining the communication posses the person on other other end. It’s possible to simply disconnect the communication from the other end and return to your body, but they had to figure out how to do that originally, and it took them like four or five episodes.
So, Rush uses the stones, takes possession of the person closest to the stones in the Milky Galaxy, and wakes up in the SGC. That it happened to be the doctor it was (gah, I can’t remember his name!) was pure luck. It could just as easily have been a marine or air force officer.
Also, I don’t believe that Rush talked to anyone back in the SGC. I think he checked to see if the stones worked, then zipped back and told everyone his BS.
I don’t think Rush is evil. I do, however, believe that he is egotistical. He needs to be right. So much so that he is willing to endanger others to prove he is right. Thus the reason he needed Shooter’s Daughter to understand that it wasn’t his fault. Also, this explain’s his stopping the dialing of Earth and instead dialing the 9th chevron address. He needed to prove to everyone that he could do it, and this was his last chance. The fact that it put everyone that passed through the gate in danger was never a consideration. All that mattered was that he did it.
Personally, I like his character. I like the idea that, with no external bad guy (No Ori, no Wraiths, no Gau’ould), the writters will HAVE to have all the conflect come from the people on the ship. Good and evil will become more shades of gray on this show as opposed to other SG shows.
-Chris