Hmm, I just looked over the ved. I'm not sure why I decided on the term basic text input, as the script itself is still fairly complex - not as complex as the text adventure template I was working on as that one contained a load more lines of code & lots of functions to simulate keyword parsing in multiple word sentences.
What you are saying is that you only want the key input to work on a specific scene when a specific condition is set, yes?
Check out line 88 where it says return false. You could replace that line & link the return to a condition you create somewhere inside of the editor. Name it "stop_text_input". Now replace line 88 with return Conditions["stop_text_input"].Value. Now you can toggle when text input is allowed by setting that condition to false, or true to allow it.