So the scenario most likely was that Hillary's aides transcribed the classified info from the secure system onto an "open" system, though it is very bad practice, mostly eradicated I thought, to have secure and open systems in the same room. So more likely they either brought their cell phones into the SCIF (a security violation) or printed the classified emails or wrote down the gist of the content, and took it out of the secure environment (a serious security violation) into an open area where they typed it into an email to Hillary on her unsecured server (a serious security violation).
So when this stuff was recovered from her server, it was not "retroactively classified" as the Hillary apologists claim, but the classification level of the contained information was recognized and applied.
It looks though like there were some other people who sent unmarked classified info to Hillary on the open system. Sitting there without immunity they should have something to worry about, but then again State and "Justice" seem to be determined to sweep this whole thing under the rug.
There’s a distance thing. You can’t have systems running at different classification levels within a set distance of each other in the same room. Same thing applies to phones and computers at different levels.