On Top of Seoul

Hiked up a mountain. At the top was a military outpost. I walked past a barrier toward a fence and heard a ticking noise like a motion detecter detecting motion.
Some army guys came within view & started shouting at me. It might have been scary if they weren't teenagers. As I left I think I heard one of them yell 'Hello'. It's hard to tell the difference between being mocked and genuine excitement.
View from above.
Can you drink too much Pocari Sweat?