An explosion in a cave, no matter how small the blast, will result in the precise amount of falling rocks needed to just cover the solitary entrance. The rocks will always be small enough to be carried away by hand.
Even when there are tens of thousands of bats, the guano will have no affect on air quality.
All caves have a three meter ceiling throughout the walkways.
All caves have torch sconces on the walls. If they aren’t lit when you arrive, you needn’t worry. They have plenty of fuel still soaked in them and will blaze with the slightest spark.
There is always a deep, rushing river in every cave, drinkable and free of E coli.
Masks aren’t needed in movie caves, not even in coal mines. That Black Lung disease is a myth.
All it takes to cover up an abandoned mine is a few rotted planks of wood that are nailed to the very cave itself. They will never be level and there will always be a warning, half washed away in black paint.
It is possible to walk about inside active volcanoes without special outer gear. Remember, you can always outrun lava.