So in Terminator Genisys, Sarah Connor and the Terminator are debating who's going to go back in time. The Terminator says he can't go, the electromagnetic fields would destroy his skin layer and it would take years to grow back (I guess meaning that he would look like a terminator when they got there, and he wouldn't have any cover?). He points out that his skin is basically just human skin, so it ages like theirs (a convenient explanation for why Arnold has aged...). Instead he ends up just waiting in normal time for them to arrive in the future, where he'd help them.
However, this seems at odds with the first trilogy, where he also comes back in that same energy sphere thing. Why didn't this burn all his skin off or whatever?
Is it supposed to be a slightly different device? Or was it a slightly different Terminator?
edit: Here is a link to the script, you can find it if you search the page for the first instance of "quantum field".