When debugging a script using Script Debugger as the frontmost window (which it needs to be if you want to use the function keys to quickly step through debugging without being given the "don't type on this layout!" error), accidentally hitting the Escape key will close the Script Debugger, which means the script will take off unchecked. This is dangerous, as a developer may be using Script Debugger to make sure the script won't damage data or cause other unintended changes.
So, a suggestion: the Escape key should definitely not directly the Script Debugger, as this can lead to data loss or data integrity problems. Potentially-destructive changes should not happen without confirmation. If the keystroke remains as a method to close Script Debugger, it should at least require confirmation.