I've made a very similar script to that few scriptcore versions ago and it had very major problem your script doesn't deal with either - font changes.
You apply "flash" by printing huge ||||||| to the player. If the player changes his font, the width, height and thickness of the character changes - therefore your flash might not be on the screen.
While this wouldn't be a problem for a casual gamer, it actually is - different languages use different fonts (check Polish vs English, ther fonts differ iirc.)
gl in future scripting