No, secret rooms are only in the Jail maps, not the graveyard crypt and mausoleum. These barrels were behind a solid wall, with no way to access them.
Update: my sorceress encountered more out-of-level barrels so I tried teleporting to them. She ended up standing on a ledge outside the wall and was able to smash the barrels. I had to teleport to return to the hallway.
Apparently the game engine doesn't always draw the walls to accurately match the floors. This can lead to trouble later when the floor is populated with objects.
Haven't seen another morphing floor tile since the one I reported.
Update: my sorceress encountered more out-of-level barrels so I tried teleporting to them. She ended up standing on a ledge outside the wall and was able to smash the barrels. I had to teleport to return to the hallway.
Apparently the game engine doesn't always draw the walls to accurately match the floors. This can lead to trouble later when the floor is populated with objects.
Haven't seen another morphing floor tile since the one I reported.