Audio Can't seem to time audio to play?

I have the following code, but the button click sound doesn't play when the button is pressed. I can set the wait time to be a million seconds, and it doesn't work.

Code (CSharp):

1.     private void Awake()
2.     {
3.         source = GetComponent<AudioSource>();
4.     }
5.  
6.     // Use this for initialization
7.     void Start () {
8.         screen.SetActive(false);
9.     }
10.    
11.     // Update is called once per frame
12.     void Update () {
13.        
14.     }
15.  
16.     public void OnExit()
17.     {
18.         screen.SetActive(true);
19.     }
20.  
21.     public void OnNoPress()
22.     {
23.         source.PlayOneShot(button);
24.         StartCoroutine(Wait());
25.         screen.SetActive(false);
26.     }
27.  
28.     public void OnYesPress()
29.     {
30.         source.PlayOneShot(button);
31.         StartCoroutine(Wait());
32.         Application.Quit();
33.     }
34.  
35.     IEnumerator Wait()
36.     {
37.         yield return new WaitForSeconds(0.25f);
38.     }
39. }