Parrot Struck by lightning while indoors

I have built my home in a cave, I had my parrot sitting in a room inside with closed doors, it was raining I could hear the thunder and lightning, suddenly a message appeared saying "(parrots name) was struck by lightning" I wanted to know how he was killed by lightning when there was a roof over his head with no rain getting inside and the doors closed how did lightning strike through the roof of stone and dirt thanx