A couple of things. My first instinct was to say not to apply, but then I thought about it a little more, and I think I'd apply.
1. At some level of business school (in terms of rankings), a 730 is good enough to get you in. You have decent grads and a STEM degree undergrad, which I think means something. You are not going to get into a top-15 school with your current profile, but I could see this playing below there.
2. You want to get into consulting or I-banking. That's quite broad, as someone else said, and makes basically no sense. Do you just wnat to make money? I thought lawyers could do that pretty well, but what do I know. This makes me assume that you don't have a Summer Associate job right now, and your prospects for full time employment are a bit slim. That's fine, as the law market is god-awful right now, but that would make me go away from saying "graduate law school, work a few years, and then apply", because if your puttering around with some contract lawyer or paralegal stuff, I think that hurts you. AdComs will think, why can't this guy get a job out of law school? Can he get on out of our school?
3. Let's say your GMAT and decent grades will get you into a school ranked around Vanderbilt, who apprently waved your fee (makes sense to me - you boost their average GMAT by 50 points). That's a good enough school to get you into consulting, albeit not McKinsey. A quick look at their employment report indicates that 21% of the Class of 2013 went into consulting. Sticking with other schools in the southeast, I think you'd have a fighting chance at Emory and Georgia Tech, a long shot chance at UNC and Texas, and a good chance at SMU, Texas A&M, and other schools like that. These schools will all give you a shot at consulting (obviously the top end schools like UT and UNC do much better than the lower end). You absolutely need to get someone to help you develop your story (read: Admissions Consultant). Somehow, combining law, biology, and business school to develop reasonable and doable goals (maybe healthcare/pharma consulting?).
4. Assuming you apply next year in your 3L year, experiment with networking with some consulting jobs. You will have a shot to get a job at a halfway decent firm like Navigant or other risk management firms/disputes and investigations firms. It's possible that you could circumvent all this b-school business, and the extra $100k of debt by getting a consulting job out of law school. You will likely not get a banking job so I'd forget about that.
5. As for debt, because of your solid GMAT, you have a shot to get money from some of these schools, which could assuage your debt fears. Speaking of which, how did your GMAT go on test day? I would almost never advocate retaking after a 730 (I got the same score on my first try and never considered retaking), but in your case, every 10 points can help you get into those top end schools. I simply don't see most of those schools rejecting a 750+ with good grades and well-executed apps.
Those are my thoughts. Sorry for the length.