@ScottDeWar_jr:
@Knightfall what part of the wall/hallway has already been 'altered'?
The western wall opposite the doors leading into the portal room. It includes the six squares along that wall. The two directly opposite of the open doorway and two squares to the north and two squares to the south. The construction done by Phelix altered the wall and the floor of those squares, as well as the hidden room.
The magically-treated walls and floors of those squares are compromised, so that stonework is at -4 to save vs. Vinny's
stone shape spell, if he choose to cast it in round 2. The stonework on the other side of the corridor does not have any penalties to save vs. the magic. So, Vinny's stone shape could work, partially work, not work at all depending on the saves.
(I cannot remember if I'm supposed to roll for each square altered or for each 10-foot section. The latter seems more reasonable.)
Note, however, the alteration of the stonework was well executed, so it isn't apparent unless a character is a dwarf (or a kobold, etc.) or has at least 10 ranks in a related skill, such as Craft (stonemasonry) or Knowledge (dungeoneering). Thus, while the other PCs might have mentioned the secret room to Vitus, he cannot
notice the altered stonework without a successful check (including Search).
Since the basic check to locate the secret sliding, stone door that leads into the room is a DC 25 Search check, then DC 25 is what is needed to notice the altered stonework. Note that opening that door without prior knowledge of its mechanism is a DC 35 Open Lock check. Since the PCs know where the sliding door is located, it is only a DC 25 Open Lock check. They did not open the door. The ex-guards opened it from the inside.
The metal door is a false door and was a poorly added addition by Phelix. Thus, the Search DC for that square is only 20.