Failure caption for a shortcut key on a text entry box

Senario: You are requiring a learner to enter specific information in a text entry box and Hit a particular short cut key to enter. Problem: if you enter the correct information and thenclick the mouse or press the wrong key no failure box pops up. A failure box only pops up if you enter the wrong information and then press the right key. I want to display a failure caption if the learner entere the wrong information OR if she presses the  wrong key. Has anyone found a work around for this. I tried using a click box with the same short cut key and no action, but what it will do is display the failure when you are typing in the text entry box.

Thanks in advance if you have a solution!!