I'm having a bit of a hard time understanding your post.
But if I understand your question correctly, it's right on the Show Choices event command:
View attachment 263302
Change it to Cancel: Disallow, and pressing Escape will do nothing.
As a side note, you might want to think about how you're using variables. Just looking at your event, it looks like you could save your variables and use switches instead.
Why do you need to have separate variables for "ok" and "no ok"? Just use one switch for "ok" and check whether it's on or off.