The metal cube flew from his grasp at an incredibly high speed, piercing through any obstacle in its path—what appeared to be the hospital doors and walls to Ashis and the others—before it slammed against some hard object and flew back.
Retrieving the space-time item, Ashis said, "This place is enclosed; unless the instance space is completely destroyed, there's no way out."
In situations where space-time items can't be used, tearing down an instance space is extremely difficult. Not to mention, being inside it without knowing the exact boundaries of the instance—demolish the hospital? What if the boundary of the instance lies in a space of chaotic overlap?