The Goat Gate is, in fact, little more than a tiny path leading away from Ekrund, providing access to the outlying goat farms. While it was no doubt heavily guarded by watchful quarrelers, the gate's greatest defense was how easy it was to miss for the casual observer. It was never found by goblin scouts, allowing several families of dwarves to escape the hold with their lives when the greenskins overran Ekrund's defences.
Even today, Slayers seeking their deaths and expeditions seeking riches alike use this pathway to enter the lost hold. Those that do seem to simply vanish into the mountain's stone walls, and while none have returned, the greenskins inhabiting the hold remain oblivious to its existence.