You're not being very helpful here,
You have the distance function dead wrong too.
you have distance(1.x, 2.y, 1.x, 2.y). you're measuring nothing. of course the event would NEVER trigger.
you need to input distance(1.x, 1.y, 2.x, 2.y) or distance(charcolision.X, charcolision.Y, policecolision.X, policecolision.Y)
I'm sorry for not being able to detect such a basic problem on my first try. I hope you can forgive me.