Loki was not locked in a room by himself. There was a lift mechanism in the hall, and Stark had just raised the cage, leaving him on display in the hall like an animal in a zoo.
The bars of the energy cage used energy circuits from the Devouring Engine and were incredibly sturdy. Loki kept hammering them, but they did not budge.
Although he had noticed that this Thor was different from the one he knew, he only assumed Thor had changed after visiting Earth. So he still forced himself to shout, "Damn you, Thor! You actually dared to set a trap for me! You will never earn the All-Father's approval, you will never—"
With a swish, the energy bars vanished.
Loki stared in disbelief as the only barrier between himself and Thor disappeared. Then he realized the cage's bars had been protecting him.
The pressure from facing Thor head-on was immense, even greater than when Loki faced Odin alone. Thor simply stared at him coldly, and all of Loki's vicious words clogged in his throat. He could not force out a single one.
"Y-you..." Loki looked bewildered, even horrified. It took him several seconds to react.
Not long ago, he had learned the secret of his birth from Odin. He had confronted the All-Father solely with indignation and grievance, and those emotions had yet to fade.
Sensing Thor's icy attitude, Loki grew even angrier. Were they not even going to pretend anymore? Were they already impatient to kill him, just as they had killed Laufey?
"Thor, whatever trick you're playing, I'll make you regret it!" Loki snapped. His instinct for self-preservation had been completely aroused, and he tried to force the other party back with an even more aggressive attitude. "You should be ashamed of what you've done!