LOUD self-checkout volumes

I understand some customers are hard of hearing and need louder self-checkout volumes. But for me it is painful and there's no emergency mute button.

Some self-checkouts do have a volume control but it usually takes a tap and a slider and several other maneuvers to make the hurting stop. This is terrible design. And even the ones that have some volume-adjusting functionality will still override, and return to full volume, when it's reached the final stages of check out.

WTF??