Is this the military base and what can I do there?

Just when I played gta 5, I wanted to explore a bit more the map and by chance I found this "base".

I tried to get in there but when I drive through the barrier there's this gate. When I went against it by car, only my car broke down and some soldier came to my car. He looked at me and shot me, I got 2 stars, but I escaped.

Is this the military base and what can I do if I come in?

I took the pictures with the xbox and made screenshots about the app.

Fly in with a helicopter. That's how my friend did it

No, that's not the military base, that's the jail.

The base is on the other side of the island

Thanks for the information

So you can't do anything there?

No problem

Where can I find helicopters? I've only been playing GTA 5 for a week

At a hospital, for example, or at the police station steal.