The Mighty Nein 1x7 | Full Length

Yeah, Essek knew that the Dynasty wouldn't allow any study of the beacon, not even for someone as high status as him. He's still in his 'first life', he's naive, book smart but street stupid. Trent likely put on the warm, manipulative front like he did with Caleb, and promised Essek he just wanted to know about dunamancy, to study it alongside him until they found a cure. Then Trent showed his true colours, and it was too late by then. So when his mother's dying wish was to get the beacon back, and Verrat pretty much signed his death warrant by threatening to tell the queen within 24 hours, Essek had to do what he had to do to stay alive and fulfill his mother's wish. This episode was hard, the group splitting up, and then thankfully coming back together. You've got Fjord and Jester looking for answers from their gods and not really getting anything meaningful. Molly and Beau just learning there's great danger on the horizon. Caleb and Nott trying to effectively suicide-by-cop in their own ways. Now we've got the heist on the eve of the Harvest Close festival. Whether they succeed or not, there's likely a long winter of hardship ahead of them.

Spoiler for anyone reading before watching Re: Essek, I take it that being the one to kill his Mother broke a part of him especially since he doesn't subscribe to their faith. In his grief, he probably saw Verrat as responsible since he figured out how to cure Typhros and his mother turned herself over to the Bright Queen. And he summed up in his words to the Bright Queen about balance and countering injustice with justice.

Fun fact; Verrat is a German word. It means "betrayal"