[quote=@chukklehed]
The Zero Eye sees more than just the future. Since the crystal is being used as a veiwing device, Sharon can use it in reverse. (Until Marcus notices and shuts her down)
[/quote]

Since you didn't put that into the CS, I'm going to say no. I already would have a problem with seeing into the future as a power but I suppose I okayed it once. 

Anyway, yeah. She can't know that Marcus is connected to the Snake. Just no. That will probably be revealed to the group much later when it comes about.

Also, the crystal is simply the device he's using to control the creature. He's using magic to see what the Snake sees.