The second floor is a bit less dangerous than the first, with the Black Knights replaced by more Manticores and some solo Chimeras. Since you were fighting groups of these in the Tower of Mirage, just one won't be much of a threat. Stone Golems are highly resistant to magic but go down very easy for something made of stone. They do hit hard, and if one gets off a Slow1Spell that affects your front line they can cause some problems, but that's unlikely.
The second floor is similar to the first, but with eight outside rooms instead of four. You start in the north and the teleporter to 3F is in the south. The Treasure here is amazing, including a Ribbon, the ADAMANT, and both the White and Black Robes. Don't miss it!