I could be wrong, but - the 'Fourth Dimension' is Time, isn't it? According to H.G Wells, anyway; the Time Traveller travels through time by moving through the Fourth Dimension. How can time be a trap for goat-legged Demi-Things, let alone goat-legged Demi-Things that bash the laws of physics against a hard surface until they shatter, then jump up and down on the remains?