Original Commentary
Looks like Kimberly hit a sore spot on poor little Emily.

Modern Commentary
We do not see Rod in the comic. I'm not 100% sure if Rod is real or, if he is real, if he knows that he's taking Emily out. I don't think we had any plans for him; we just put it out there in case our future selves could make something of it. Six months later, Emily is dating David, though.
Maybe they went on a few dates, realized they weren't right for each other and moved on like mature adults. Or maybe Emily started dating David to make Rod jealous and accidentally got into a long-term relationship.
I'm also not sure what engineering would even do in terms of a chemical research company. - Terrence