curry

I had a curry at coco1 restaurant with my co-workers yesterday. One of us orderd "5kara" curry. "5kara" means level of hot. That's middle one. I usually eat a curry with "1kara". It's very enough for me. I couldn't believe what he orderd. When our dishes arrived, only his one had different coular from the others. I tried his curry a bit. It was pretty spicy and I thought I would never try this one. Don't his taste and stomach have something wrong?