It sounds like theres someone under the hood on a seesaw!
https://drive.google.com/file/d/0B-lQFiR2JdF7d3JQTUFUcklQWm8/view?usp=sharing
https://drive.google.com/file/d/0B-lQFiR2JdF7d3JQTUFUcklQWm8/view?usp=sharing
I think someone else on here had a similar squeak/rattle and it was the front shock absorber mounts, although it sounds like it's coming from the dash area. I'm fairly sure it got looked after under warranty so it's probably worth a trip to your local MB dealer to get it checked out. Best of luck.It is a creaking sound you can only hear from inside the cabin - seems like it is coming from the middle of the dashboard