Call of Duty Finest Hour easter egg: the giant apple

So this is a quite long video and I can't help it, it's literally the biggest easter egg in the game and the tank is slow, but this video will show you all there is to it in this easter egg.
At the start of the mission Op. Little Saturn you have to fend off a Stuka attack, after you've done that look to the left and you'll see a single dead tree, if you go just a little to the right of it you can go trough the wall and that'll end you up a mountain road wich leads you to the area to explore. The con here is that if you've done all this it's impossible to do the rest of the mission, when you enter the base the rest of the map isn't loaded and you'll get in a very hard to control float if you go further.