No matter how Bosh·Garon's heart image space transformed, turning into palaces, plains, cities, or ruins, the essence of the place the two found themselves in was ultimately just a tomb chamber that wasn't particularly large.
And there was only one entrance and exit to the tomb chamber, which was the door through which Mo first entered.
Simply put, if one wants to leave here, as long as they possess the ability to see through the illusion to reality, they can simply walk out through the door that always exists in this space, with almost no difficulty.
In fact, although entering Bosh·Garon's mounted space from the Land of Buried Bones isn't easy, it's best to find someone knowledgeable to guide you if conditions allow. However, simply leaving Bosh's tomb chamber is actually quite straightforward.
