so i am making a hard mode but the values are not changing can you help?

so in another script i have it setup to run the hard bit of the script but the values dont change in game

{
public Rigidbody Player;
public float m_speed, rotatespeed;
public bool failSafe;
void Start()
{

}
public void HardMZ()
{
    if (failSafe == false)
    {
        m_speed =- 200;
        failSafe = true;
    }
}
void FixedUpdate()
{
    if (Input.GetKey(KeyCode.W))
    {
        Player.velocity = transform.forward * m_speed * Time.deltaTime;
    }
    if (Input.GetKey(KeyCode.S))
    {
        Player.velocity = -transform.forward * m_speed * Time.deltaTime;
    }
}
void Update()
{
    if (Input.GetKey(KeyCode.A))
    {
        transform.Rotate(0, -rotatespeed * Time.deltaTime, 0);
    }
    if (Input.GetKey(KeyCode.D))
    {
        transform.Rotate(0, rotatespeed * Time.deltaTime, 0);
    }
    
}

}

Could you also post the other script that calls “HardMZ()”?