That “tonearm” (cartridge-slider, actually) is reminiscent of the Revox B790. Only thing missing from the B790 was a central spindle clamping mechanism so it could be wall-mounted. Because the cartridge carrier had to constantly adjust itself, it could also register hits and spring the cartridge up and out of harm’s way. So one way to stop playing mid-record was simply to grab the arm and rotate it 90 degrees, no fuss no planning, just grab it and crank. If you’ve never seen one, check https://stereonomono.blogspot.com/2011/12/revox-b-790.html .
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