thank god of thunder i wait with the few nerds to watch the ending .. all left after the foo fighters walk and some movie soundtrack u will see the ending .

you can watch crappy youtube if u miss it

So in the last scene of the movie Dr. Selvig played by Stellan Skarsgård meets up with Nick Fury played by Samuel L. Jackson, in some kind of government S.H.I.E.L.D. location. Fury is standing in front of a table with a large metal box/case on it. They go on to discuss some recent discoveries that Selvig has made in relation to some of the alternate universes. Fury then asks Selvig for his advice on something… and that’s what is in the case on the table. Fury opens up the case and inside is the the Tesseract or Cosmic Cube linking the film to Captain America. Selvig then asks what is it, Fury tells him that it is a source of incredible power. After he says this the camera moves a bit revealing what is supposed to be Selvig’s reflection, but it’s not. Instead we see a reflection of Loki played by Tom Hiddleston. So Loki is actually possessing Selvig. Loki responds to Fury with… “That’s very interesting…” Boom, end.

I didn't really understood the sneak scene.

Did it mean the Doctor was Loki in disguise? Or was loki just hiding and spying?

What was in the briefcase that is related to AVENGERS ... some power source?