It appears you are right about open('con'...).

However, this issue is about the fact that 
>>> import time; time.sleep(10)
^C
...
KeyboardInterrupt

works in the console but does not work in the IDLE Shell in default mode.  In default mode (-n not on the command line) entered code is executed in a separate process and and ^C causes a message to be sent to the separate process to simulate ^C keypress by calling 'something'.

The indirect process works for 'normal' code like
>>> s = input('Hi')
so input() is not part of this issue, except that it or its interruption should not be broken.  Ditto for
>>> while True: pass