Light can bounce or absorb depending on the color. Here in the south, it absorbs more than reflects. Although it is not much of a problem around here, over exposure in light colored rooms can also occur. The auto thyristor should recycle from .5 to 11 seconds. This however, is not a bad thing since most shots require maximum output any way.
Film is cheap.
If forced to change film while underground, avoid leaning over the camera as dust and dirt could enter from your clothes or helmet. Enhance a point and shoot. It is possible to use a standard point and shoot camera with slave units and get better results. Build upon your assistants suggestions for camera angles. Show your pictures.