How do I subtract from timer behaviour when it's currently running?

I have an enemy in my game that spawns randomly and upon spawning, it will chase the player for a random amount of time across multiple layouts before it disappears. Now what I want to do is that every time the player moves to another layout it will subtract from the said on-going timer a random amount, as to speed up the timer.

I know the expression I can use is -random(a,b)

But there's only start/Stop/pause/Resume options for the timer behaviour so I don't know where to put this expression...

How should I go about this now? Thanks in advance!

You can restart the timer with a shorter time. For example, this is the remaining time of the currently running timer minus 1 second:

Object.Timer.Duration("tag")-Object.Timer.CurrentTime("tag")-1

dop2000

Thanks! It works perfect and I learnt new expressions :>