While I believe that PRPL has the same 1000000-opcode-per-frame limit as CRPL, I have a slightly different issue.
I've managed to inadvertently lock up the game through a script with heavy large list use (which was logging the list regularly). This managed to freeze the game (though PRPL.txt kept expanding) while remaining well within the opcode limit. If alt-esc (or some such) could prevent further script execution while in edit mode, that would be nice.
Of course, this will be a feature of use only to the minority who need to debug very heavy scripts, so it may not be worth it. I'm tabling the suggestion in case it is a simple two-line change.