Private Sub Workbook_Open Event Problem

Hi...
I have a macro that verifies some data in the workbook after it opens. If this data is ok the Workbook Open event lets the workbook open, else it saves and closes it.
Now the problem is: as you may or not know if you open excel, and through the open menu try to open the same file again but this time with shift key pressed on, this time Workbook Open Event will not run and all the workbook with all the macro will work.
So what i though was to add some sort of code that (as the Workbook Open Event was disable but all macros still works in the file) make after 30 secondes or less run the piece of code that was in the Workbook Open Event and like this verifies the data again and if the data was not ok, it still closes the work book.
The thing is i don't know how to make a code run automaticaly after workbook open event is disable. If i do i could make it count 30 seconds and after this run the macro.

Any ideias?
I though add the code to another key macros in the workbook so if the user trigger any of then and the data is not ok it automatically closes the workbook. The thing is that this approach will make this macro keep running everytime that the user pressed some of the buttons that contains this macro, and that's why i would like a timer function, because this procedure would only run once.

Thank you.

Good idea. If i hide all worksheets when the workboook close and just let menu visible when it opens with shift pressed on, workbook open will not work but if not works all sheets will remain hidden. Good idea. I'll just add a timer of 30s to run the code in the workbook open event so if i need to change something i'll be able to enter in vba mode.
Now just for asking, is there some way to prevent workbook close event like there is for workbook open? Because if there is, a user also could stop workbook close event (if the code is correct) and like this keep all sheets visible when opening again without workbook event on.

From what i'm searching there is no way from preventing it, because it comes from the close button.
Thanks for the idea.