Pielorinho
Iron Fist of Pelor
Valesin, two points.
First, you can also do it when you have superior cover, which can still let you be seen; it grants an advantage in this respect (essentially making it nearly impossible to hit you, and giving you combat advantage when you have superior cover).
Second, you can move from that position of total concealment to a position of only partial concealment/cover, maintaining the advantage. The party enters the room and attacks. You stealth and move forward to a position of partial cover/concealment and attack. Or you can even run outside the room, stealth, and come back in with a sneak-attack.
Daniel
First, you can also do it when you have superior cover, which can still let you be seen; it grants an advantage in this respect (essentially making it nearly impossible to hit you, and giving you combat advantage when you have superior cover).
Second, you can move from that position of total concealment to a position of only partial concealment/cover, maintaining the advantage. The party enters the room and attacks. You stealth and move forward to a position of partial cover/concealment and attack. Or you can even run outside the room, stealth, and come back in with a sneak-attack.
Daniel