Well, it sounds like you shouldn't be putting in more applications until you really figure out what days you'll be available for the other job. I think you should talk to your boss or human resources at your current job and see if they can get you on a set schedule. When/if you can get that, then you can tell your other potential employers what days you can work for them. But it does sound like transportation is an issue. Trying to bus between your home in Maryland and your job in Philiadelphia, that's got to take up some time. If you can, I would try to find something more local, but I know jobs are hard to come by. I don't know your situation, obviously, but if you could possibly get your own car, that would be a great convenience to you. Also, I don't know what your school situation is, if you're going to school, you're likely going back from summer vacation within a month. Can you still juggle the two jobs? If the answer is no, its unlikely that a place will hire someone that can only commit to working for a little over a month.
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"Violence begets violence." -John Lennon