moo got out last night

so last night I got home REALLY late from a show (around 1:30am) and I opened my door and usually moo sees me coming from the window and runs to meet me by the door and so when I open it he is looking at me from the couch. He has done this for about 2 years now. (never once has he shown an intrest in the outside so I'm never worried) Anyway...last night I come in as usual and before I close the door (I close it quickly anyway because of tilly)he JUMPS over me and out the door...I FREAK out and rush out to get him (my neighbors must thnk I'm nuts since I was yelling -Oh no you don't! Get back in here this instant!!) and he froze and I tried to pick him up but he RAN around the porch area and back into the apartment. So i slam the door shut and lock it and he comes up and starts to rub against me and starts to rub up against everything in the apartment and was meowing...and attached himself to me for the rest of the night...

now I know he has been having litter box problems...does anyone think there is a connection or even why moo would WANT to go outside? Or even what was the whole rubbing up against me thing was about? (I'm glad it was FREEZING last night and there was ice on the porch..I think that detered him from running down the stairs) I do have him mirco chipped in the event that he does get out like that.

Mine did that, he is 10 years old, now he decided he wanted to see whats out there and darts between my feet out the door. When he got out he didn't like it at all it was very cold and icey, I grabbed him and brought him back in. They do that. They get curious. He's rubbing on you because he's very happy he's back in, and probably doesn't want you to be mad at him. What is the litterbox problem?

Is he neutered? Might be looking for some action.

Sometimes they will do this to get attention, Almost in spite like you left me alone all day so I'm going to run outside. Some are terrified of the great outdoors, some are curious. I will tell you that you should be extremely careful to not let him run out again. The more they get out, the more courage they build up and further they will run. Years ago my kitty Cleo got out and wouldn't let me catch her. I had to stop chasing her since she was going towards a highway. Hours later she finally came back and had been attacked by something. 2,000 dollars later and almost loosing her, she never did it again.....

He may be smelling or seeing another cat outdoors.