I don't fully understand your question, maybe because it wasn't clearly stated but I do have a general idea of what you're talking about. What I understood from your post is (correct me if I'm wrong) that you are curious about when leaning hard you seem to gain more speed? Maybe not necessarily leaning but you are really digging in your edge? If this is what you are trying to explain in your post I understand. It is just the way the boards are made. It is a universal thing with all boards. For example I ride a Rome Agent and I get the same reaction out of my board. But what is happening is when being on your edge you are on the sharpest point of your metal edge which means, there is little to no resistance on the board to slow it down. It is similar to thinking of it as like a knife. When cutting through a loaf of bread for example the knife will cut better when using the sharp edge opposed to a dull edge. And also you mentioned something about not being able to control speed when you are doing that action. This is because in order to stop and/or slow down you need to be sliding or creating some resistance and like I had said earlier riding an edge hard like that creates little to no drag. So in order to slow down you would need to ease up on your edge a bit and allow the bored to slide until you reach desired speed then you could continue your run. Also you mentioned as well about the board coming out from under you? That may be caused by dull edges. Just get them sharpened and you should be good after that. Sharp edged don't tend to slide out as often as dull ones. Well I hope this helped answer your questions man I wish the best of luck to ya!
If you live in the NB area and ride sugarloaf, feel free to hit me up via forum message!