At one point during the game, you will be forced to fight a thief in order to get a number of items contained within his room. Fighting the thief is quite hard unless you have the stiletto which he holds, assuming you can even get it: luckily, this glitch will let you get it early, making defeating him much easier. In the room below the thief's, enter the room above and type and enter "Get stiletto". Assuming you fail, go back down, then type and enter "G". In doing so, you will get the stiletto instantly, despite the thief not being in the room to steal the stiletto from: now you can just go back up and kill the thief with the stiletto.