Oneshot--MSG (embassy) and MSF (watching nukes on a boat) are both open to all MOSes.
That being said, Marine MPs are well trained and given good equipment and support.
The very best? National Guard MPs on active duty.
With calls of "Po-leece" and "gimmie your shit now" and "shut up, you penis kissing tramp" (to men, of course) and "you ain't got no mark, bitch" (to a wife on the self slap face and call the MPs post deployment divorce plan), and taking a quick snort on duty, and showing up hung over every shift for a week, and getting off a mid shift at 7 am and cracking the first of many beers at 7:10, and blasting past gatherings of diverse soldiers, who enjoyed blasting NWA fuck the police when they saw you, and pumping easy e or ghetto boys through the PA, that is just the way to police.