Sarah being here did help. Without Sarah, he had little to focus on beyond the abyss within, and like a wise man once said, you couldn't stare at that for too long. Not only that, of course. As the gaudily dressed Cowboy had pointed out on more than one occasion, Eric had attachments. Sarah was one of them, and her presence was enough to ease the tide of sorrow and rage somewhat. The fact that she was also pretty good at being his own personal Jiminy Cricket didn't hurt, either. He just hoped he never drove her away. He didn't really want to think about it, but it had been getting worse, since the Lazarus Group.
He had to cut that thought off before it could go further. Thinking about the Lazarus Group lead to thoughts of Shelly, and after the price she'd paid to help him, thoughts of Shelly almost always lead to more anger than he knew what to do with. Not at her, but at whatever cosmic forces were playing puppeteer with their lives. It wasn't good for him to think about them.
Instead he focused on Sarah. He forced his darker thoughts back into the back of his mind. At Sarah's reaction, Eric's lips twitched up, which for him was the equivalent of a chuckle from someone a little more expressive. "Of course I came," he told her softly, returning her hug with one arm. "I wasn't going to leave you to figure this out alone."
When she sat back in the chair and prompted him to explain, some of the little signs of happiness faded from his face. "Right. I do." He wasn't going to insult her intelligence by trying to spin some stupid story. She may have been a kid, but in some ways she was older than she should have been, and he wasn't going to patronize her. That didn't mean he was going to like explaining it all, but she deserved the truth and, more importantly, he knew she could handle it.
Okay, so maybe he'd underplay the apocalypse a little. He wouldn't lie about it, but he didn't need to make a big deal out of it, either. He spent a few seconds considering what he was going to say, his body relaxing somewhat. He adopted the birdlike posture he'd become so used to since his return from the grave, perched on the balls of his feet, his arms crossed and resting on his knees. "...I'm going to warn you ahead of time that it's going to sound pretty ridiculous." He knew Sarah trusted him, and knew she would believe a lot, but this was big enough that even she might give it some pause.