The only reason I am saying it is irrelevant is because a) it doesn't change anything, and b) it isn't compelling at all.
I work on a boat. The job pays well, but unfortunately there is a bare minimum of employees available to do the job. The LSAT falls on my particular shift, and there is one other person available to cover me in the event of an emergency. That person has responsibilities (or perhaps is just a dick), and has not been able to cover those days. My boss encouraged me to register each time, telling me that he can't make any promises, but should he be able to find coverage he would. It hasn't happened. I haven't even had a vacation in the last 4 years.
That job is all I have right now. Again, I have two kids who rely on me. I would never want to jeopardize my employment. It isn't a pretty story, but it's the truth. It may sound Ebenezer Scrooge-ish, but it is what it is. Sorry it isn't glamorous.
Thanks for sharing. I think it is a compelling story precisely because of the background. Not everyone is in such a situation where this kind of employment is tolerable. You definitely should explain it, and have your boss write a LOR and stress the importance of your presence on the boat, which caused you to miss test after test. I don't really think it is a good deal, but better not leave them wondering why.
I do wonder how you will be able to afford to go to law school, but that's off topic and I respect if you don't want answer. I don't think I could ever live with your job precisely because of my kids. I can't imagine working a job where I can't get free if my kids need me for whatever reason. Good luck with law school, and securing better employment.