Recall Potion

A mirror does the same job, but the animation is long enough that something can land a hit on you partway through it. The potion is over almost before you have registered pressing the button. That gap is the difference between bailing out of a fight that has gone wrong and dying in the attempt, so it belongs on the hotbar, not in a chest.

These pile up on their own. Pots and chests hand them out constantly and slimes cough one up now and then, so there is no reason to ration them the way you would a single mirror. Use one to skip a walk home. Use one to reset after a failed run. The supply refills itself.