better support to pause/break while loops when they break and never end would be nice. now they just cause mirc to not respond eternally with no way to fix it except to end process mirc.exe
i have only experienced this by chance and cant reproduce it.
Just as a side remark, one explanation could be that your script has :error labels - they'd intercept the ctrl+break presses, and depending on how your script works, could have the effect you're observing.