What you'll need:
JVS (For trust checks)
Homing Missile (For lovey aiming)
Zone Events (This will make aiming easier)
Then take my english and turn it into events (No, I'm not doing it for you).
You'll need a JVS door that only opens on Trust Level 1. Take away all sound effects, and make it fire a relay to the turret on rejection.
When the player enters the zone near the turret you made with bricks, have it send a relay to the JVS door mentioned earlier. If they pass, they have your trust, and it stops there. If they don't pass, they don't have your trust, so a relay is sent to the turret. The turret then fires a homing missile.