If you're not in a triple-quoted string, typing ;; is guaranteed to produce a syntax error, which breaks you out of the current "chunk". But yes, it would be great if you could use the [X] button to do that. (I think in Pythonista 1.4 that was possible and the feature was somehow lost in 1.5.)
Welcome!
This is the community forum for my apps Pythonista and Editorial.
For individual support questions, you can also send an email. If you have a very short question or just want to say hello — I'm @olemoritz on Twitter.