Detecting a unit/player on foot and disabling a looped script

[NGagedFX 10]

I'm bussy with an IED script in which I want the IED to be triggered only by a BLUFOR unit (preferably a player, don't know for sure yet) on foot. I was using:

Charge Init:

[this] exec "IED.sqs"

IED.sqs:

_bomb = _this select 0
_target nearestObject [MEN, _bomb]
?((_target distance _bomb < 4) && (side _target == West)):goto "BOOM"

It worked fine when using CAR instead of MEN, and it would activate as a HMMWV came close, but while using MEN, it didn't matter what kind of dance I did on top of the IED: it didn't go BOOM.

Also, this script loops every second. Does anyone know how to use another script to disable thos script? I want to be able to remove the IED functionality using the action menu.