If you don't want the audience to hear what John actually says, perhaps because of battle sounds or loud foreground music then you use the abbreviation MOS.
John pleads MOS with the driver to move faster.
If you want audience members who can lipread German to know what he said, then you can be a bit more specific.
MOS, John pleads in German with the driver to move faster.
But in that case you might want to specify exactly what he says, in which case you're back into dialogue.
John pleads with the driver, but cannot be heard over the explosions.
Please move faster!