I had a buddy apply for his MMD, he went to the same place I did years ago, which was Concentra. They’re all over the country. Bring the paperwork in that you need to print out from the NMC website, and tell them you’re paying for it out of pocket, and it shouldn’t be a problem. They deal with Mariners pretty frequently, just double check that they’re DOT certified, though I haven’t heard of a Concentra that isn’t.