Gargoyle Guardians

At the bottom of the grand staircase, a resonant mechanical rumbling emanates from a dark shaft opening up in the middle of this chamber’s floor. Four large four-armed gargoyles stand perched over the shaft, each about ten feet tall, featuring a tiny slot in their backs.

Any character looking down on the room from one of the balconies above or another high vantage point notices something else:

Embedded into the head of each gargoyle statue is a metallic tile. Starting with the northernmost gargoyle and going clockwise, the tiles are copper, silver, gold, and platinum.

Four giant four-armed gargoyles are perched atop the pedestals, each one crouched within its square of tiled precious metal. The gargoyles remain motionless until they are provoked.
The slots in each pedestal are 4 feet above the floor and roughly the size of a standard coin. All humanoids must pay a tithe before leaving this room to avoid provoking the gargoyles’ wrath. Specifically, each humanoid must insert a coin of the appropriate type into each pedestal (1 cp in the north pedestal, 1 sp in the east pedestal, 1 gp in the south pedestal, and 1 pp in the west pedestal). A gargoyle will always accept a more precious coin than the one required, so a character inserting a platinum coin into every pedestal could exit the room safely. A gargoyle will also accept a tithe of multiple coins of equal or greater value (10 cp instead of 1 sp in the east pedestal, for example). The pedestals have hollow cavities within them to store the coins (see “Treasure” below).
The gargoyles always know when they’re being cheated. If any humanoid leaves the room without offering sufficient coin, any cheated gargoyles spring to life and attack the cheapskate. A gargoyle also springs to life and attacks if it or its pedestal is damaged in any way. The metallic tiles atop the pedestals can be pried loose, but they turn to dust if removed from this chamber.
Shaft
The shaft in the floor is 10 feet wide and 15 feet deep. It opens into the ceiling of The Cog of Rot (area 58). To scale the smooth walls of the shaft, a character needs climbing gear or magic.
Treasure
Each gargoyle is a hollow on the inside and magically enchanted to be more resilient to damage. Reducing the gargoyles to 0 hp causes them to break open and spill their contents.
The north gargoyle holds 5 sp and 100 cp. The east gargoyle hides 1 gp, 120 sp, and 200 cp. The south gargoyle conceals 2 pp, 90 gp, 350 sp, and 500 cp. The west gargoyle holds 10 pp, 630 gp, 7,200 sp, 5,000 cp, and the skeletal remains of an Omuan engineer.