To obtain entry: claim a darkened shard from /claim then examine it and go to one of those teleporters (avoid the abductors). Access quest is A darkened shard parts 1 and 2.
To obtain a teleport crystal: perform part 2 of the access quest to receive a glowing shard. Then you can teleport from anywhere in Norrath to Splitpaw, and then go to the Lower Tunnels teleporter, select Thundering Steppes and zone right to this door.
Why would you want to? Well, there are two epic zones in here, and another epic mob near coldwind point, until you get the glowing shard you can't access the epic mobs in splitpaw.
