You can use the "wait" action (System -> Wait), but it only works for time.
What you are asking for sounds more like a sub-event, though.
For instance, here:
<img src="http://i.imgur.com/3TEPyMG.png" border="0" />
It checks the selected item variable, and if the player is falling. THEN, if these conditions are met, he checks to see if the player is pressing Z.