Alright, while I am able to deny this I'll allow Key to decide (The Server Vice Manager) and give my explanation. I explained that you didn't ambush anyone, you simply went onto the mountain and killed two people, I don't see how you yourself didn't see that that wasn't an ambush and was simply an attack on the main base.
It's also worth noting the first thing you said to me when i asked what you were doing was 'If you read the rules' that to me shows that you knew you were doing something that could get you told off and you did it anyways.
Finally, nothing has to be specifically stated in the rules, if the staff member in question (Me) decides it's a breach of the rules they are within their right to warn you.