This question already has an answer here:
In the opening scenes of Avengers, we see that Loki is apparently bullet-proof. Furthermore, we see that Asgardians are overall immune to small explosions and similar attacks.
So why did Loki surrender after his fight with Captain America, when Stark appeared at Stuttgart, Germany? Was it part of his plan, or was he genuinely wary of Iron Man’s arsenal?
In a later conversation, Captain asks
“I wanna know why Loki let us take him.”
And if so, what were his intentions behind letting SHIELD take him?