Save just the first number or text?

I want to save the first info that I get in a textbox or numberbox. I'm making a quiz-button patch. So when some one is pressing their button I want their name to come up in a text box and a sound playing. I have that but if someone is pressing their button after the first one their name will come up in the box and the sound will play again.

So I want a way to "close the floor" after the first pressed button.