Intra_word_emphasis are disabled, so the underscores in that first part should show up normally. There's a long-standing bug that the preview doesn't handle this correctly, but it should show up normally in the post.
If you still have an _ that is causing you trouble, you can escape/hide it from the markdown parser with a backslash (\).
Update: I came back to this now nearly 5 years later because this just got a new upvote today. I believe that the markdown rendering has been completely re-written, probably twice with the whole CommonMark thing, since I first posted this answer (probably twice with the whole CommonMark thing), and I have no idea how accurate it is anymore.