Is there a way to teach him the differnce?

I take Levi & Jordan outside on a leash and harness sometimes. Normally Levi gets to go out because he seems to know that when the harness goes on he can go outside, but without it he needs to say in the house.

Jordan on the other hand now wants outside every time I open the door. I've taken him out twice in the last 2 weeks. After the first time he ran out the door the first several times I came home, then he stopped. I thought we were making progress because on Monday I put the harness on him & he ran right to the door like he knew what it was for. Then last night he tried to escape again when I came home.

He loves to explore and before his cancer progresses too far I want him to have as much fun as possbile. Any suggestions for how I can get him to understand he only goes outside when he has the harness on?

I think someone before suggested putting the harness on then putting the cat in the pet carrier and carry the pet carrier out so that they associate the pet carrier with outside and not the door

My Zane will sometimes rush out. I will block him with my foot and say NO and he will stop. Sometimes he's so quick I can't stop him, particularly if something happens to distract me. However, he never goes very far. He just goes out onto the porch and lies down, looking back as if to say, "Aren't I clever." He waits for me to come over, pick him up, and put him back inside. I think he likes the attention.

I always put the harness on at the door and I take it off as soon as we come back in. They have never tried to escape harness-less.

I'm afraid Jordan's done going out. First when I got home he tried to run out the door, then after I took him out and brought him back in he spent hours staring at the door and howling. It's hard though because he sure loves it, and he ate like a champ last night & this morning.