Dreaming about a rain of stones?

I dreamed of a rain of stones, and promptly rushed into a garden-shaped building with two friends that looked like a place selling hot drinks. Someone was driving a car behind, running for his life through the rain of rocks, as if he was trying to get in. But there was a robot-like thing that stopped them, and they had no choice but to force it. But one of them had a knife on his calf, and had to cut off his calf to save his life. Another one was cut open at the heart. They bled a lot. The staff couldn't stop the robot even by scolding it. The staff kindly held the injured person lying on the ground for last-minute comfort. I was very scared in the dream. Two friends were a couple and they were talking and laughing. Said that if their car could withstand this rain of stones.