Hola,
No logré captar exactamente lo que quiere decir la imagen. (Podrías por lo menos usar diagramas de flujo

)
Tengo algo que más o menos comprendí, con 2 botones en el Form:
Public Class Form1
Private a As Integer = 0
Private n As Integer = 0
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim n_local As Integer = n
n = n + 1
Do
Application.DoEvents()
Loop Until (a = 1)
MsgBox("Hola" & n_local)
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
a = 1
End Sub
End Class
Espero te sirva

SaluDOS!