Unity 3d Elevator Script Not Working Properly

Hello all, I'm working on an elevator script that is built off of the lift example in the official tutorials. I want my elevator to move up and down, stopping for several seconds at the top and bottom for the player to walk in and out.

However, I cannot get the elevator to stop during the timer. What's more, the player falls through the elevator when he walks in. Can anyone give me any tips or answers?

Thanks

 using UnityEngine;
 using System.Collections;
 
 public class Elevator : MonoBehaviour
 {
         public float timeToDoorsClose = 1.4f;
         public Vector3 pointB;
         public float liftSpeed = 3f;
         private GameObject player;
         private bool playerInLift;
         private float timer;
 
         void Awake ()
         {
                 player = GameObject.FindWithTag ("Player");
 
     
         }
 
         IEnumerator Start ()
         {
                 var pointA = transform.position;
                 while (true) {
                         yield return StartCoroutine (MoveObject (transform, pointA, pointB, 3f));
                         yield return StartCoroutine (MoveObject (transform, pointB, pointA, 3f));
                 }
         }
     
         IEnumerator MoveObject (Transform thisTransform, Vector3 startPos, Vector3 endPos, float time)
         {
 
                 var i = 0.0f;
                 var rate = .05f / time;
                 while (i < 1.0f) {
                         i += Time.deltaTime * rate;
                         thisTransform.position = Vector3.Lerp (startPos, endPos, i);
                         //transform.Translate(endPos * liftSpeed * Time.deltaTime);
                         yield return null; 
                         //timer += Time.deltaTime;
                         
                         /*if (timer > 0) {
                                 thisTransform.position = endPos;
                         } else {
                                 thisTransform.position = startPos;
                         }*/
                 }
 
             
         }
 
         void Update ()
         {
 
                 if (playerInLift)
                         LiftActivation ();
 
                 
                 if (transform.position = pointB) {
                         
                         timer += Time.deltaTime;
                 } 
 
                 if (timer < timeToDoorsClose)
                         rigidbody.isKinematic = true;
                 else                
                         rigidbody.isKinematic = false;
         
                 
         }
 
         void OnTriggerEnter (Collider other)
         {
 
                 if (other.gameObject == player)
         
                         playerInLift = true;
         }
 
 /*        void OnTriggerEnter ()
         {
             timer += Time.deltaTime;
         }
 */
 /*        void OnTriggerExit (Collider other)
         {
 
                 if (other.gameObject == player) {
                         playerInLift = false;
                         timer = 0;
                 }
     }
 */    
         void LiftActivation ()
         {
 
                 player.transform.parent = transform;
             
             
                 //transform.Translate(Vector3.up * liftSpeed * Time.deltaTime);
             
             
         }
 }