Shhhhhh... this is a secret.
You have found a secret room. This is what is called a hidden mission. You have to look long and hard to find these. They will not be in plain site. The hidden missions will usually earn you much bigger rewards than normal missions. Some things may only be available through hidden missions. If you find one, you have one of two choices. The first is to post on the public board for everyone to know about and we all can have a chance to complete the mission. The second is to keep the information for yourself and not tell anyone and be the only one in the fleet to have the rare loot that you found. How you play is up to you. Help everyone, or show off something only you have found.