Is there a way to force a second edit of a page, rather than re-editing your previous edit? This can get annoying if you re-edit and then accidentally hit cancel.
This is currently not possible.
There is no danger in hitting cancel, when re-editing. Your first edit remains.
Although it seems I just discovered an odd bug: while the first edit remains on the page (as is intended,) the entry disappears from RecentChanges. I have to look into that.