Doors

I cannot think of what to say about this one. I considered talking about Nigel but he has honestly been good lately. He has not gotten into one single thing lately that he should not have. Plus, more shockingly, he has even been acting as if he likes me. Claude loves me beaucoup, Ollie loves me lots, Henry likes me, Nigel tolerates me. But lately, that boy seems to be warming up to me. Once, Nigel ran away. I opened the back door and he skidaddled like the wind. I never expected to see him again. His attitude has always been that I kidnapped him and that I am holding him hostage. He stayed gone all day the day he ran away. I went outside looking for him high and low but no Nigel was to be found. Finally, I got mad and gave up. How dare he run away from me when I was providing him with such a good life? Late in the evening when the darkness first began to fall, I looked out my back window and saw little boy coming out from under the fence stretching. Obviously, he had been sleeping all day. I knew not to bother him. I am pretty good about second guessing the feline mind and I knew he was thinking about coming home but not yet. I would wait him out. After a couple of hours, I opened the back door but little boy kept sitting by the tree not yet ready to come up to the house. I closed the door and turned out the porch light. About an hour later, again I opened the back door. This time, boy came crashing into the den faster than greased lightening. I do not know what he saw out there but something changed his mind. Suddenly, the great outdoors was not so appealing to a kitten. He got a dose of flea medicine then, all was right with the world.
Doors. My Nigel got out one but came back through the same door. What does this door mean?