"Svartalfheim? Of sorts. We had not access to the Bifrost--the 'rainbow bridge'--but a similar method was used to arrive. The method that brought me here, however, while similar in nature, was not the same energy as the Bifrost. If you are looking for an exit through the Bifrost, allow me to stop you here. I have already tried. Extensively. Embarrassingly so."

He might be being helpful. Only because they have a similar goal in that respect. He wanted out of here as badly as the rest of them, even if he did claim all that awaits him is death on the other side. "I will provide, and you may extend this knowledge to the rest of your little team, whatever assistance you wish in the interest of escape. If it is my magic you require, I will lend it. My knowledge? That as well." And for once, he isn't lying. Does that tell you how badly he wants out of here? "In return for my cooperation, I ask only to obviously be included in our escape."

Loki's eyes narrowed slightly when he made that offer, because he wouldn't put it past any of them to use his skill and ditch him here while they left. What reason did they have to take him along? Again and again, he was to be used for his power then hung out to dry. Odin, Thanos, Thor, each to different degrees were guilty of it.