Question Agent goes up the floor one floor at a time

Hello. I created a simple building and I want agent to go up the floor one floor at a time.
I made the code below, but agent goes up to the top floor at once. How should I solve this?

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using Unity.MLAgents;
5. using Unity.MLAgents.Sensors;
6. using Unity.MLAgents.Actuators;
7. public class AgentControl_3Floor_Lv0 : Agent
8. {
9.     Rigidbody rBody;
10.     public Transform Water;
11.     private int nowFloor;  // Agent's floor
12.     private float AgentSpeed = 0.5f;  // Agent's speed
13.     private float FirstWaterHeight = -10.0f;  // Water's height at Initializing
14.     private bool onEpisode = false;  // During Episode?
15.     // At Initializing
16.     public override void Initialize()
17.     {
18.         this.rBody = GetComponent<Rigidbody>();
19.     }
20.     // Spawning Agent
21.     public void SpawnAgent()
22.     {
23.         this.transform.localPosition = new Vector3(Random.Range(-19.5f, 19.5f), 1.5f, Random.Range(-14.5f, 14.5f));
24.         nowFloor = 1;
25.     }
26.     // Episode begin
27.     public override void OnEpisodeBegin()
28.     {
29.         onEpisode = false;
30.         this.rBody.angularVelocity = Vector3.zero;
31.         this.rBody.velocity = Vector3.zero;
32.         this.transform.rotation = Quaternion.identity;
33.         SpawnAgent();
34.         Water.localPosition = new Vector3(-25.0f, FirstWaterHeight, -20.0f);
35.         onEpisode = true;
36.     }
37.     // Collecting observations  size = 4
38.     public override void CollectObservations(VectorSensor sensor)
39.     {
40.         sensor.AddObservation(this.transform.localPosition);  // x, y, z
41.         sensor.AddObservation(Water.localPosition.y); // y
42.     }
43.     // Choosing Agent's action  size = 4
44.     public override void OnActionReceived(float[] action)
45.     {
46.         Vector3 dirToGo = Vector3.zero;
47.         Vector3 rotateDir = Vector3.zero;
48.         int act = (int)action[0];
49.         if (act == 1) dirToGo = transform.forward;  // forward
50.         if (act == 2) dirToGo = transform.forward * -1.0f;  // back
51.         if (act == 3) rotateDir = transform.up;  // right rotation
52.         if (act == 4) rotateDir = transform.up * -1.0f;  // left rotation
53.         this.transform.Rotate(rotateDir, Time.deltaTime * 100f);
54.         this.rBody.AddForce(dirToGo * AgentSpeed, ForceMode.VelocityChange);
55.         if (this.transform.localPosition.y < Water.localPosition.y)
56.         {
57.             AddReward(-1.0f);
58.             EndEpisode();
59.         }
60.         // Reward step by step
61.         if (nowFloor == 1) AddReward(0.6f / MaxStep);
62.         if (nowFloor == 2) AddReward(0.8f / MaxStep);
63.         if (nowFloor == 3) AddReward(1.0f / MaxStep);
64.     }
65.     // When touching something
66.     public void OnTriggerEnter (Collider col)
67.     {
68.         // During Episode?
69.         if (onEpisode)
70.         {
71.             // Touching UpStair
72.             if (col.gameObject.tag == "upStair")
73.             {
74.                 this.rBody.angularVelocity = Vector3.zero;
75.                 this.rBody.velocity = Vector3.zero;
76.                 this.transform.rotation = Quaternion.identity;
77.                 int xPosPuls = -1;
78.                 int zPosPuls = -1;
79.                 if (this.transform.localPosition.x > 0) xPosPuls = 1;
80.                 if (this.transform.localPosition.z > 0) zPosPuls = 1;
81.                 nowFloor++;
82.                 this.transform.Translate(xPosPuls * -1.0f, (nowFloor - 1) * 7.0f + 1.5f, zPosPuls * 4.0f);
83.                 this.transform.Rotate(0f, xPosPuls * -90.0f, 0f);
84.             }
85.             // Touching DownStair
86.             else if (col.gameObject.tag == "downStair")
87.             {
88.                 this.rBody.angularVelocity = Vector3.zero;
89.                 this.rBody.velocity = Vector3.zero;
90.                 this.transform.rotation = Quaternion.identity;
91.                 int xPosPuls = -1;
92.                 int zPosPuls = -1;
93.                 if (this.transform.localPosition.x > 0) xPosPuls = 1;
94.                 if (this.transform.localPosition.z > 0) zPosPuls = 1;
95.                 nowFloor--;
96.                 this.transform.Translate(xPosPuls * -1.0f, (nowFloor - 1) * -7.0f + 1.5f, zPosPuls * -4.0f);
97.                 this.transform.Rotate(0f, xPosPuls * -90.0f, 0f);
98.             }
99.             // Touching Obstacle
100.             else if (col.gameObject.tag == "obstacle")
101.             {
102.                 AddReward(-0.6f);
103.                 EndEpisode();
104.             }
105.         }
106.         else
107.         {
108.             SpawnAgent();
109.         }
110.     }
111.     // When touching Wall
112.     public void OnCollisionEnter (Collision col)
113.     {
114.         // During Episode?
115.         if (onEpisode)
116.         {
117.             if (col.gameObject.tag == "wall") AddReward(-0.6f);
118.             EndEpisode();
119.         }
120.         else
121.         {
122.             SpawnAgent();
123.         }
124.     }
125. }