Next:

*Note, you can always put something else after the timer stops, I'm just using Game Over as an example
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Next, go to Tools -- Database --- And Click on the common events Tab. Make a common event, set the trigger to none, and set the timer to whatever time you want it at. (Make sure to name the common event)
(I doubt you need an image for that, but I'll put one up anyways)

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Then, make another common event, also set it's trigger to none and set it so that it calls up the common event that we just created.

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If you were doing this for an escape event than you're all done, otherwise continue reading tutorial for how to apply this to an item
If you want to do this for an item, simply go to the items tab and make a new item (consumable {Unless you're planning on doing something else with it}). Go to common event and select the event used to call up the timer. Now if the item runs out, you'll get a game over. (or whatever else you chose to do with it)

And there you have it! A timer that allows you to use it outside of battle! You can also view the instructional video to see this in action.
*Note: This was done in RPG VX. It may not be compatible in VX ACE.