Randomize how many times a shrieker goes off before it summons a warden

As it is right now, it's very predictable raiding an ancient city. The player knows exactly how much they can push before a warden shows up and they have to leave. However, it'd be a lot more interesting if you randomized how many times the player can make sound before they have to deal with a warden. I think 2-6 times is a good range - it should be at least two to keep one mistake from being disastrous. Having it this way will let players push their luck, hoping that if they open this one chest that it won't be the one to set them off, which will greatly contribute to the tenseness of visiting an ancient city.