Do you realize that when Loki learns about his mother, how pissed he will be? And not only on the dark elves- first and foremost at his dear golden brother, who dragged his little human pet to Asgard and Frigg had to protect her? And you know how well it turned out?
You know, Loki will definitely seek revenge from Malekith- but he will also definitely seek retribution from Jane and Thor! So when we see Jane tortured and Thor, well, injured- may be it is not at all a trick, may be Loki is doing it all in his right mind because he is hurt and pissed!