tl;dr - hitting Ctrl-C at any point in any Python program can produce undefined behavior.
Feeling better about not landing that Python job every day.
"Most notably, a KeyboardInterrupt may appear at any point during execution. Most Python code, including the standard library, cannot be made robust against this, and so a KeyboardInterrupt (or any other exception resulting from a signal handler) may on rare occasions put the program in an unexpected state."