Timer in P3

I’m still hacking away at a timer. I want the timer’s time delay to update but I can’t seem to get it to work. It stays with the initial settting.

create ()
{
let sond = this.sound.add(‘sond’);
let t = this;

    this.lambda = 1;
    this.next = 1;
    
    let timedEvent = this.time.addEvent({
         delay: this.next * 1000,
         callback:  tick,
         callbackScope: this,
         loop: true

    });

     function tick(){
       t.next = -Math.log(1- Math.random() / t.lambda);
       sond.play(),           
    }    
          
}

update(){

    this.input.on('pointermove', (pointer) => {
             if(pointer.x < 400){
                 this.lambda = 4;
             }
             else if(pointer.x > 400){
                 this.lambda = 1;
             }
    });

}