Heres a Script for SloMo hold left shift

using UnityEngine; using System.Collections;

public class ShiftForSloMo : MonoBehaviour {

public int SetSlomoSpeed = 0;

// Use this for initialization
void Start () {

}

// Update is called once per frame
void Update () {

    if(Input.GetKeyDown(KeyCode.LeftShift))
    Time.timeScale = SetSlomoSpeed + .3f;

    if(Input.GetKeyUp(KeyCode.LeftShift))
        Time.timeScale = 1f; 
}

}