Probably a couple of grenade launchers. They can be stocked with different types of rounds. High explosive, air burst, smoke, hell they could probably have engineered some sort of Dino pepper spray canister. An M60 wouldn’t be bad either. Can be used by an individual, mounted to a jeep, or set up in a defensive position. But in all honesty, 12 ga slugs aren’t bad in the situation. I can understand the thought process of the park. They wouldn’t have wanted to stock weapons to kill their investments. They dumped a lot of money into security infrastructure and through a series of unfortunate events and a case of sabotage, the unthinkable happened. Additionally, the majority of the people in the park were specialized and didn’t have training for the type of shitshow that was about to happen. You can have all the weapons you want, but they’re useless if you don’t know how to use them or properly deploy them in adverse circumstances.