In the room immediately following the yellow door, there is a section of the northern wall not covered in grime. Open it to find a teleporter. (sector 134)
Enter the teleporter in secret #2 to reach the stone tower outside, where you can get two medikits and a soul sphere. (sector 130)
In the corridor around the gray platform in the east, a section of the west wall has vertical bands on it. Open it to find a medikit, a box of ammo, and a bulk cell.
Another similar alcove can be found in the south of the area, where you can get a medikit, a box of ammo, a box of shells, and a box of rockets. (sector 176)
Another wall with vertical bands on it can be found in the east side, but does not open when pressed on. After flipping the switch at the end of the hall, return to this area to find a cell, a plasma rifle, and a megasphere. (sector 177)