I've noticed that some players are unfamiliar with Mystcraft, and with the dangers of entrapment, so I've decided to post a few methods for escape that work on this server. For players new to the mod, reading a Link Book or Descriptive Book and clicking the colored panel will take you to another dimension, called a Mystcraft age. Dying in a Mystcraft age will NOT return you to the overworld, and entering with a book does NOT provide a way out, so it is very easy to become trapped in one.
METHOD#1: Don't get trapped in the first place! If you enter any unfamiliar Mystcraft age, always bring at least one Link Book back to the overworld, and a book stand or lectern to place it on. Even better, bring a diamond locked Ender Chest with multiple Link Books and other supplies in it, and place it as soon as you enter. In any case, its always a good idea to build a safe room around the spawn platform, just to keep the creepers out.
METHOD#2: Find a Star Fissure! Star Fissures look like large cracks in the terrain, leading all the way to bedrock, with a shimmering portal at the bottom. Star Fissures are very rare, but jumping into one will take you back to the overworld.
METHOD#3: Find a Dimension Door! Dimension Doors are found in most ages, and look like ordinary doors with a shimmering portal inside. These lead to a series of dangerous extra-dimensional dungeons, and eventually to the overworld. Avoid the traps, don't let the red Monoliths see you, and always look for the wooden doors. If you end up in Limbo, dig into the ground, avoid the Monoliths, and look for pools of red.
METHOD#4: Build a Nether Portal! If your age has resources, look for wood, iron, flint, and lava. To avoid the need for diamonds, use a bucket and some dirt to shape your portal out of lava, then cool each block in place with water. Once you light the portal and enter the Nether, you can use the same portal to get to the overworld.
METHOD#5: Craft another Descriptive Book! This may take you to a better age, from which you can escape. This should be used as a last resort, due to the need for multiple resources, and the danger of further entrapment. You will need wood, iron, water, sugar cane, leather, and either ink sacs or black saplings. Leather can be produced by cooking rotten meat in a redstone furnace. Sugar cane can be replaced by crushing logs in a pulverizer, then making paper from the wood chips. Make sure to bring a Link Book that leads to where you started, and take the same precautions advised above.
METHOD#6: Ask for help! If another player can get to the book you used, they can bring a Link Book and get you out. The rescue party will only get one shot at saving you, so make sure to do what you can to help them. Fortify the spawn platform with walls and torches, and make sure the area is clear and creeper free. If you decide to rescue another player, make sure to bring everything you need to survive and escape, including Link Books, lecterns, food, torches, and building materials. Also, a hostile player could make things much worse, so make sure to ask someone you trust!
