MBA Cost Over 2 years = ($180,000)
Did you include the loss of two years income in that figure? That could bump the cost up well over $300K.
With the student loans it sound like you will be around 30 by the time you get your net worth back up to zero after getting the MBA.
The way you are currently saving you will easily have a net worth of well over half a million by the time you are 30, possibly even close to million if the stock market does well over the next seven years. With the way that the compounding of savings works you would also likely have enough in your retirement accounts when you are 30 to already completely fund your retirement.
Draining out your retirement accounts in effect has a higher cost since the tax advantaged space is worth a lot and you will never get that back no matter how much your earn. If you are not fully vested in any employer match in the 401K you may lose that too.
Finding a GOOD MBA program that you could take in the evenings while working might be a more cost effective option. It might not be as highly rated a program as the one you are looking at but you would also be getting work experience at the same time which could help your career some.
Lots has been written questioning which MBA programs are cost effective. Be sure to research this well and look at what all the MBA graduates earn, not everyone that starts the program will finish and half the students will earn less than the average starting salary so the value of the degree is hard to figure. Also watch out for "average" figures when the median number should be used.