Arduinna

Ooh, good catch on Tony shaking off the sceptre's influence! I didn't think of that, but it makes sense given his resistance to Loki later at Stark Tower. I've got a theory that it's because Tony's arc reactor is powered by the same element that makes up the Tesseract and the orb in Loki's sceptre. The reason they could shut down the wormhole is because the Tesseract element couldn't work against itself (Natasha sticking the sceptre past the forcefield).