I am using Safari 5.1.7 ... hitting esc always toggles it from normal to markdown mode, but toggling back to normal is difficult ... I have to click around in the different panes a few times and keep hitting escape, and eventually one of them will work.
Is it indeed supposed to toggle back and forth with escape, pressed once, regardless of which pane your mouse is in ?
Safari actually fires key events for the escape key hundreds of times per second.
This can cause some unexpected behavior if you don't do some clever javascript to handle this bug.
I came here to comment on the same issue - hitting escape to edit will work for the first toggle, but afterwards to say 'i'm done editing' the key handler gets called too many times and the markdown flickers on and off like crazy.
Also: escape is not really a normal key for 'edit this text'. It would be better to put an explicit 'edit' link, it's more understandable for your users.
Overall though I like how simple it is, and love the use of Markdown.
I think the esc key toggling is a fantastic idea.
I was just about to switch my wiki platform to vimwiki, but this is making me rethink that...