Is There a Thought Process Involved?

I'm just wondering about how the minds of little boys work. See, my little one (we'll call him NT, short for Naughty Toddy) woke up last night in the middle of the night because he had wet the bed. So I got him all cleaned up and back to bed when he asks for a drink of milk. My rule is that if he wets, he doesn't get any milk. I'm not cleaning up a peed bed twice in one night! Usually he grumps a little, says ok with a scowl and then is good. Last night, he didn't like that answer. He started to cry so I told him he couldn't wake up his brother. He calmed down and I thought that was the end of it. Nope. An hour later, he woke me up again asking for milk. And he had been awake since the first time he woke up. I said no again and put him back into bed. About 7:00am, I heard my older boy stirring around so I decided it was time to get up. When I got into the bedroom, I saw that NT had obviously been up and been busy for some time. The light was on, the blinds were open, his blankets and a few extra that he had pulled out of the closet were spread out over his bed and the floor.

Long story short, who knows how much sleep NT got last night. As a result, he was quite the grump this morning. And clumsy. I don't know how many times he came running up to me in tears because "I hurt myself!" Very sad boy today. So about 11:30am he wanted to go outside and when I told him no, he threw a royal fit which resulted in me putting him in his room until he calmed down. When he finally stopped yelling, I went to check on him and let him out. He had opened the window and since it was still a little chilly, I closed it again. As I was closing it, I noticed a trail of liquid running down the porch roof from the window. Knowing my boy and knowing that there wasn't any water in the room, I immediately knew he peed out the window! When I asked him, he 'fessed right up and his only reason was "Because."

So here's my question, what makes him think of doing something like that? Or did he think at all? Was it just a "crime of opportunity"?