Player slows down when he looks back

In the game, I am making. The player is being chased by bulls in a straight narrow path.

So how do I make the bulls speed up when the player looks back
(at the bulls)?

Can you guys provide example scripts or tips I can use to make this?

So far he is my script

using UnityEngine;
using System.Collections;

public class Rotation : MonoBehaviour {public Transform target; public Transform target2;
	

	// Use this for initialization
	void Start () {

		
	}
		
	
	// Update is called once per frame
	void Update () {
			
		if (Input.GetKeyUp(KeyCode.R))
			iTween.PunchRotation(gameObject,iTween.Hash("looktarget",target.position,"easetype",iTween.EaseType.spring,"time",4.5f,"delay",.1f));
		
		if (Input.GetKeyDown(KeyCode.R))
			iTween.PunchRotation(gameObject,iTween.Hash("looktarget",target2.position,"easetype",iTween.EaseType.spring,"time",3.5f,"delay",.2f));
		
	}
	}

is “target2” the bulls you’re looking at? There’s heaps of ways you can do it, but probably the simplest would be to have a bool set to true when you’re looking at the bulls.

so:

// declare the variable somewhere
public bool isLookingAtBulls;

void Update()
{

     if (Input.GetKeyUp(KeyCode.R))
    {
        iTween.PunchRotation(gameObject,iTween.Hash("looktarget",target.position,"easetype",iTween.EaseType.spring,"time",4.5f,"delay",.1f));
        isLookingAtBulls = false;
    }
        
     if (Input.GetKeyDown(KeyCode.R))
    {            
        iTween.PunchRotation(gameObject,iTween.Hash("looktarget",target2.position,"easetype",iTween.EaseType.spring,"time",3.5f,"delay",.2f));
        isLookingAtBulls = true;
    }
}

then in whatever script controls your bulls velocity, check if the ‘isLookingAtBulls’ bool is true and set it’s velocity to the faster one. If it’s false set it back to the slower velocity.