Faster reacting Comparator

I am making a fully working FNAF 2 Minecraft multi-player gamemode! I plan to publish it when I am completely done and fixed all bugs. This isn’t a bug, it’s just that I have the right idea, but I don’t know how to do it! As you may know, in FNAF 2 when certain animatronics get into your office or near it, you put on the spare Freddy head to fool them into thinking you are one of them. I have made this feature but I have to use a comparator to detect the player putting it on! And it is a few ticks (1-3) to slow! It’s a tiny diffrent you might think, but it’s not fair if he is holding it and in those few ticks the animatronic kills him. Any help on how to make a instant reacting comparator-type command creation? Thanks.