I can’t remember if some of the UAVs are wire guides or all RF but they work fine until someone stomps on them

And fluids, like water and air(?), don't come through by themselves, if the gate is inside a large body of that fluid. If it's a stream of grain or soup, it does go through though. Oh, and gravity can come through.

yes. I definately see that. I guess its to way if you can move at the speed of light.

doh. I got nothing with stargate then then wracked my brain and was like. its chevron something.

In one of the SG-1 episodes, the gang is stuck in some kind of underground jail where the captors just throw people and food through the gate. There’s no DHD on the jail side. So some of the prisoners try to escape by going into the wormhole but it’s the wrong way. Some also let themselves get swallowed by the woosh.

Gang escapes by using some mcguffin electric tree roots and manually dialing the gate.

Each connection is one-way. They need to close the connection and connect back to go back.

That's also why they have so many problems of not finding a dialing device on the other end.

The shield is for hostiles incoming. I think that was established within the first episode, you dial in, send the code, and the shield isn't used. And the movie set up the one way part, otherwise there's no plot to find the dial home address.

That's just how that physics works. You can't have a water slide go both directions.