The marshall doesn’t go inside the conference room where they privately meet and I can’t find anything that outlines what authority they would have to do something that involved physically restraining a justice in general. Seems to me the impeachment procedure in the house is the only way to stop a justice that was going absolutely ham.

This is a pretty extreme scenario though so maybe they would intervene anyway if a judge brought a whole ass loudspeaker in especially since maybe that could be seen as a physical threat to the other justices so idk banana phone scenario is gray area probably