Hi, please could someone explain how I do this below on rmxp pls?

Basically, I got a door with a npc stood near it saying that "if you meditate long
enough clarity of mind will show you the way",.. now, what I want to do is when
your stood still infront of the door for 1 minute the door will unlock and open up
allowing you to enter, if you move away from the door then the 1 minute countdown
will stop. (the countdown will not be visible)

could sum1 pls tell me how to do this, or even better do a demo for me, i follow demos
easier than trying to follow instructions, but either will be cool.

thanks.

p.s. Im sure something similar was done on a Snes game - earthbound, where you was asked
for a password underneath a waterfall, all you do was stand still for 3 minutes and it let
you in, unless you moved away, it then reset.