54F3

This result has the RGB levels being subtracted. The yellow colour on the keyhole (195, 195, 71) were subtracted from the variable colour (255, 255, 0). 195 - 255 = 0, 71 - 0 = 71 which made the resulting colour on the keyhole. I wonder what would result if a triple digit subtracts a double digit.

More importantly, using 195, 195, 71 on the keyhole box might back the hole black.

The red green and blue values change for each object in there relative to the change from the value when the door was closed to the value when the door was opened.

The door was closed at 255, 255, 0, and set to 0, 0, 0, so red and green values dropped all the way to 0 for all colours, but the blue values didn't change.