How do they interact?
Would e.g. a Bane Spider step through the gateway for 1 MP with its front half and be teleported with its complete body to the target piece? What happens if the target gateway piece or one or both of the two adjacent spaces are occupied by a hero - is he pushed aside or is the gateway blocked?
Or does the spider have to spend 2 MP to move through the gateway? Again, what happens if the target gateway piece or adjacent spaces is blocked by a hero?