7 HP back to Gamad from Voadam's wand of cure light wounds.
Gamad, feeling somewhat better, retrieves the matte black rod segment and walks the circumference of the hexagonal chamber, tapping first the yellow gem on the northern doors, then--after skipping the now broken green gem on the eastern doors--the blue star sapphire inset into the runework on the southern doors. When tapped by the segment, the yellow-begemmed set of double doors does not react in the slightest. At lightest touch of the rod to the sapphire, however, the star inside the blue gem winks out of existence and the low rumble of stone grinding on stone resounds within the water-slogged hexagonal chamber as the set of southern doors forms a crack down the middle then part and slowly open.
Having tapped the rod to the blue gem, Gamad instantly feels his stomach go queasy with unease as his skin feels like liquid oil. Shrugging off whatever taint the rod or any magic inherent within the rune might attempt on him, Gamad blinks and finds himself facing the oddity of a solid stone wall. A corridor lined of limestone flooring, walls, and ceiling looms just inside the now open southern doors. Fully 20 feet wide and unlit, the corridor, Gamad judges, stretches perhaps 50 feet both right and left. The hallway ends in both directions when it abruptly jogs 90 degrees to the south. In the dim light shed by Voadam's gold coin, Voadam, Brakkus, and Chev find themselves confronted with a wide shadowy hallway inside the open southern doors. Gamad and Maelicent, whose eyes benefit from keen underdark senses imparted by blood alone, can see quite well into the darkened stone hall.