VB2013, Possible Arithmetic Error - vb.net

Question

In Shadowrun 5e there is a rule concerning explosives in confined spaces called the 'Chunky Salsa Effect'. I am trying to create a program that simulates the 'Chunky Salsa Effect'. I have most of the program working, however, as the size of the space [meters] increases, the number of blast reflections [bounces] increases. It should be the inverse, the blast falloff [minusMeters] should decrease the [bounces]. [walls] determines the number of surfaces the blast reflects off of. [damageDice] is equal to the base damage of the explosive [baseDamageDice] + (([damageDice]/2) per reflection). For some reason [damageDice] and [bounces] do not decrease when [meters] is increased.
Private Sub btnCalculate_Click(sender As Object, e As EventArgs) Handles btnCalculate.Click
Dim meters As Integer = 0
Dim dice As Integer = 0
Dim damageDice As Integer = 0
Dim baseDamageDice As Integer = 0
Dim bounces As Integer = 0
Dim hits As Integer = 0
Dim walls As Integer = 0
Dim minusMeters As Integer = 0
Dim explosiveType As Integer = 0
Dim ap As String = "-"
Dim diceRoll As Integer = 0
Randomize()
walls = CInt(txtWalls.Text)
explosiveType = cbExplosiveType.SelectedIndex
If explosiveType < 0 Then
explosiveType = 0
cbExplosiveType.SelectedIndex = 0
End If
Select Case explosiveType
Case 0
minusMeters = 1
baseDamageDice = 18
ap = "+5"
Case 1
minusMeters = 2
baseDamageDice = 16
ap = "-2"
Case 2
minusMeters = 4
baseDamageDice = 24
ap = "-4"
Case 3
minusMeters = 4
baseDamageDice = 24
ap = "-10"
Case 4
minusMeters = 1
baseDamageDice = 23
ap = "+5"
Case 5
minusMeters = 2
baseDamageDice = 21
ap = "-2"
End Select
diceRoll = CInt(Math.Floor((6 - 1 + 1) * Rnd())) + 1
If diceRoll >= 5 Then
hits = hits + 1
End If
dice = baseDamageDice
For x = 1 To walls
meters = CInt(txtMeters.Text)
damageDice = baseDamageDice
Do
damageDice = Math.Round(damageDice / 2)
dice = dice + damageDice
meters = meters - minusMeters
bounces = bounces + 1
Loop While meters >= 0
Next
For i As Integer = 1 To dice
diceRoll = CInt(Math.Floor((6 - 1 + 1) * Rnd())) + 1
If diceRoll >= 5 Then
hits = hits + 1
End If
Next
lblHitsPerBounce.Text = Math.Round(hits / bounces)
lblTimes.Text = bounces
lblResult.Text = dice
lblNumHits.Text = hits
lblAPOutput.Text = ap
End Sub