The Instant Fortress magic item has the potential to deal a great deal of damage (~55 on a failed save, more than a 9th level Fireball spell). Many adventurers who acquire this item attempt to weaponize it. The text for the Instant Fortress reads:
You can use an action to place this 1-inch metal cube on the ground and speak its command word. The cube rapidly grows into a fortress that remains until you use an action to speak the command word that dismisses it, which works only if the fortress is empty.
Each creature in the area where the fortress appears must make a DC 15 Dexterity saving throw, taking 10d10 bludgeoning damage on a failed save, or half as much damage on a successful one. In either case, the creature is pushed to an unoccupied space outside but next to the fortress. Objects in the area that aren't being worn or carried take this damage and are pushed automatically.
In order to activate it, "You can use an action to place this 1-inch metal cube on the ground and speak its command word". Rules as written, it seems like the activator will be caught in the "blast radius" of the expanding fortress. Is that true? If so, are there any ways for the activator to avoid the "blast"?
A bit of background: I usually play at Adventurers' League tables. Most of those tables try to play as close RAW as possible. My motivation for asking this question is to gain a better understanding of how an Instant Fortress functions according to RAW. If RAW is ambiguous, I would greatly appreciate a logical explanation of how it should reasonably function.