If you want to prevent a pyramid from returning to your inventory, you can put it in a container, but since the pyramids were not designed to be able to teleport you between maps, they only check the coordinates of the other teleporter, not the map. If you leave a teleporter in one of the homestead chests, for example, and then use the other in Cyseal, it will teleport you near where the 2 drunk guards were before getting to town. Coordinates of a chest or NPC on one map could put a character out of the normal game area on a different map, or in the middle of a group of opponents, etc.