As a logged in user with access to VE in MobileFrontend, bring up a random page and click the pencil icon to edit with VE e.g. http://en.m.wikipedia.beta.wmflabs.org/wiki/0.6922277312143298#/random.
Note that in the upper left, the back-arrow icon "escape" button appears before the other controls.
Click the back-arrow escape icon as the page loads, before the page is finished loading. Nothing happens.