Silverfish accidentaly make dark rooms underground while mining

If triggered, silverfish will break out from their block. But this will happen regardless if the block is exposed or not, so if you are mining in a mountain biome and you trigger some silverfish to break out, they might do it inside the walls creating little dark pockets/rooms, in which hostile mobs can spawn, impairing mob farms etc

So I suggest this change: silverfish will break out from their infested blocks only if said blocks are exposed to air or to water. This way a player can more easily identify the new dark spots created and light them up.