simple rotate script dont work,Simple rotation control

Hey all i try to expand an existing script

 using UnityEngine;
 using System.Collections;
 
 public class ExtendedFlycam : MonoBehaviour
 {
 
     /*
     EXTENDED FLYCAM
         Desi Quintans (CowfaceGames.com), 17 August 2012.
         Based on FlyThrough.js by Slin (http://wiki.unity3d.com/index.php/FlyThrough), 17 May 2011.
  
     LICENSE
         Free as in speech, and free as in beer.
  
     FEATURES
         WASD/Arrows:    Movement
                   Q:    Climb
                   E:    Drop
                       Shift:    Move faster
                     Control:    Move slower
                         End:    Toggle cursor locking to screen (you can also press Ctrl+P to toggle play mode on and off).
     */
 
     public float cameraSensitivity = 90;
     public float climbSpeed = 4;
     public float normalMoveSpeed = 10;
     public float slowMoveFactor = 0.25f;
     public float fastMoveFactor = 3;
 
     private float rotationX = 0.0f;
     private float rotationY = 0.0f;
 
 
     void Start()
     {
         Cursor.lockState = CursorLockMode.Locked;
         //Screen.lockCursor = true;
     }
 
     void Update()
     {
         rotationX += Input.GetAxis("Mouse X") * cameraSensitivity * Time.deltaTime;
         rotationY += Input.GetAxis("Mouse Y") * cameraSensitivity * Time.deltaTime;
         rotationY = Mathf.Clamp(rotationY, -90, 90);
 
         transform.localRotation = Quaternion.AngleAxis(rotationX, Vector3.up);
         transform.localRotation *= Quaternion.AngleAxis(rotationY, Vector3.left);
 
 
 
 
         if (Input.GetKey(KeyCode.LeftShift) || Input.GetKey(KeyCode.RightShift))
         {
             transform.position += transform.forward * (normalMoveSpeed * fastMoveFactor) * Input.GetAxis("Vertical") * Time.deltaTime;
             transform.position += transform.right * (normalMoveSpeed * fastMoveFactor) * Input.GetAxis("Horizontal") * Time.deltaTime;
         }
         else if (Input.GetKey(KeyCode.LeftControl) || Input.GetKey(KeyCode.RightControl))
         {
             transform.position += transform.forward * (normalMoveSpeed * slowMoveFactor) * Input.GetAxis("Vertical") * Time.deltaTime;
             transform.position += transform.right * (normalMoveSpeed * slowMoveFactor) * Input.GetAxis("Horizontal") * Time.deltaTime;
         }
         else
         {
             transform.position += transform.forward * normalMoveSpeed * Input.GetAxis("Vertical") * Time.deltaTime;
             transform.position += transform.right * normalMoveSpeed * Input.GetAxis("Horizontal") * Time.deltaTime;
         }
 
 
         if (Input.GetKey(KeyCode.Q)) { transform.position += transform.up * climbSpeed * Time.deltaTime; }
         if (Input.GetKey(KeyCode.E)) { transform.position -= transform.up * climbSpeed * Time.deltaTime; }
 
         if (Input.GetKey(KeyCode.R)) transform.Rotate(Vector3.forward,  -cameraSensitivity * Time.deltaTime);
         if (Input.GetKey(KeyCode.Tab)) transform.Rotate(Vector3.forward,  cameraSensitivity * Time.deltaTime);
 
         if (Input.GetKeyDown(KeyCode.End))
         {
             Cursor.lockState = (Cursor.lockState == CursorLockMode.Locked) ? CursorLockMode.None : CursorLockMode.Locked;
             //Screen.lockCursor = (Screen.lockCursor == false) ? true : false;
         }
     }
 }

i added the line for the R and TAB keys. But the camara only rotate as long i press R or Tab. But i want to have like the rest of the code.

Maybe someone can help me out .

Greetings to all.