How do I get an emergency evaluator to revert the last method change?

Hello

I have blocked my Morphic UI because I made a mistake in changing

    TextComposer>>composeAllLines

I would like to revert this changes but cannot do it because the user
interface is blocked.
The UI is just blocked, no emergency operator shows up.

Is there an option to call  the emergency evaluator to revert the last
method change.

Regards
Hannes