Two sleep at same time

[Vastyrik]

Hello

While 1
Sleep(20000)
Send("{F1}")
WEnd

While 1
    $coord = PixelSearch(0,20,1024,768,0x18555A)    
    If Not @error Then
        MouseClick("left",$coord[0],$coord[1])
        Sleep(15000)
    EndIf
WEnd

I want 2 whiles be executed at same time but there is only the first block that is executed.

[sandin]

$timer1 = TimerInit()
AdlibEnable("_adlib1", 50)
Func _adlib1()
    if TimerDiff($timer1) >= 20000 Then
        Send("{F1}")
        $timer1 = TimerInit()
    EndIf
WEnd
While 1
    $coord = PixelSearch(0,20,1024,768,0x18555A)    
    If Not @error Then
        MouseClick("left",$coord[0],$coord[1])
        $timer2 = TimerInit()
        do
            Sleep(50)
        Until TimerDiff($timer2) >= 15000
    EndIf
    Sleep(50)
WEnd