Derek looks at Erica, somewhat stunned. After a moment, he gives her a hug - careful to not squash her sandwich or get his on her - then pulls back, meeting her gaze with his.
Looking into her eyes, Derek says "Erica, I can't imagine why you'd think that about yourself, or that you have any less to offer than any of us. I certainly don't think that way about you, and if any of the others are treating you that way, you need to stop hanging with them.
"The reason I've been trying to contact Arthur and Nightfall and Atlas has nothing to do with my not trusting or valuing you. I was contacting them because Arthur was a party to the Pledge, and Nightfall and Atlas worked with Arthur and me to look into the matter in the first place. In fact, they were the ones who found Tim, and Tim was supposed to contact Nightfall with anything he found out, so I figured they'd want to know."
After a pause, he says, "Now, I'm not going to pretend I wouldn't like to have a big bruiser like Atlas or a skilled fighter like Nightfall backing us up as we look into something that might involve the Others, but that's just common sense and a recognition that they are better at some things than either you or me. That in no way suggests I don't value what you have to offer... and I mean those those things you have to offer in addition to your body and your beauty. You're more than a pretty girl I enjoy doing delightfully nasty things with in the bedroom, or the shower, or the living room couch, or bent over the kitchen table or wherever. As it happens, you're good at a lot of the same things I'm good at." Grinning, he adds "And once again, I am speaking about things other than the sex. I happen to think my strengths have served me pretty well, so there's no reason I wouldn't respect someone else who shares a lot of those strengths."
Taking one of her hands in his, Derek says, "So, let's go to the mall and do what we can to sort this out. But no more of you questioning whether you have any worth. Alright?"