Hey LL,
I don't think it is your grades, so I don't know how much taking more classes is going to help. 3.6 in science and overall in undergrad is excellent and better than my undergrad gpa and post bac combined. Plus you said your MCAT was good as well, mine too and there is no way in hell I am going to risk letting that go down. I would go for the more interesting job. That's what I am going to do. After a year of lab work and a year of working in a Path department conducting autopsies along with numerous other volunteer activities, I think I am qualified for a job with a good amount of responsibility and prestige factor. Maybe something that will get me interviews and give me something better to talk about than just why I want to go to medical school. Also a better job will give you the opportunity to get new recs which may put you over the edge later in the process when you have worked long enough to ask for one. If you want to take classes, do so but I think your free time outside of your new job would be better spent volunteering in some capacity.
I think I got waitlisted because of some low grades in my past and a late application. Well chosen recs and work experience got me five interviews. I wish there was some magic wand I could just wave and come up with the formula for how to get into medical school with what I have, but there isn't. I can only guess and come up with plans of action like that above. One more piece of advice, get a hobby. Preferably one that involves being outside. God knows having one this year would have saved me a lot of stress. If I am to go through this hellish process again I am going to keep myself as busy as I can and stop depriving myself of fun in favor of moping about an empty mailbox. That is just my two cents and what I have planned for myself. Regardless, I hope we both get in. Maybe we'll be classmates at Loyola.