XL 2013 Bloquer une feuille

Public Cptlance
Sub LancerCompteur()
    Sheets("Feuil1").Select
    ActiveSheet.Unprotect
    Cptlance = 1
    [Temps] = 10
    [Texte] = ""
    Lancer
End Sub
Sub ExecuterTimer()
    If Cptlance = 0 Then Exit Sub
    If [Temps] = 0 Then
        Cptlance = 0
        [Texte] = "Le temps est écoulé."
        Sheets("Feuil1").Select
        ActiveSheet.Protect DrawingObjects:=False, Contents:=True, Scenarios:=True
    Else
        [Temps] = [Temps] - 1
    End If
    t = Now + TimeSerial(0, 0, 1)
    Application.OnTime t, "ExecuterTimer"
End Sub
Sub Lancer()
    t = Now + TimeSerial(0, 0, 1)
    Application.OnTime t, "ExecuterTimer"
End Sub

Sub Bouton()
    Application.OnTime EarliestTime:=Now + TimeValue("00:02:48"), _
    Procedure:="VerrouilleCellules", Schedule:=True
End Sub

Sub VerrouilleCellules()
    Const FeuilleVerrouiller = 1                'A adapter
    Const MotDePasseFeuilleVerrouiller = "psw"  'A adapter
    
    ThisWorkbook.Worksheets(FeuilleVerrouiller).Unprotect MotDePasseFeuilleVerrouiller
    ThisWorkbook.Worksheets(FeuilleVerrouiller).Range("F1:F24").Locked = True
    ThisWorkbook.Worksheets(FeuilleVerrouiller).Protect MotDePasseFeuilleVerrouiller
End Sub

Option Explicit

Public Verrou As Boolean

Sub Bouton()
    Verrou = False
    Application.OnTime EarliestTime:=Now + TimeValue("00:02:48"), _
    Procedure:="VerrouilleCellules", Schedule:=True
End Sub

Sub VerrouilleCellules()
    Verrou = True
End Sub

Private Sub Worksheet_Change(ByVal Target As Range)
    Application.EnableEvents = False
 
    If Not Intersect(Target, Me.Range("F1:F24")) Is Nothing Then
        If Verrou Then
            MsgBox "Le temps est écoulé, cellule non modifiable !"
            Application.Undo
        End If
    End If
 
    Application.EnableEvents = True
End Sub