Mike has tested this on Chrome 41.0.2272.118 m, and IE 11.0.9600.17501 on Windows 7 with Vector.
We don't have a good reproducible case, but we think that the pattern might run something like this:
- Click on a redlink (not from search results) to create a new page (automatically opens in the wikitext editor).
- Decide that you want to create the page in VisualEditor rather than the (default) wikitext editor, so click the 'Create' tab to switch it.
- Discover that the page is blank and everything's crashed.
We think that the problem isn't happening in "incognito" mode, but withiout a clear sequence of reproducible steps, it's a little difficult to be sure of that. He's done the usual steps of disabling gadgets in prefs, but not (yet) tried blanking common.js and vector.js files.