Had almost that same identical thing happen to me with a .444 Marlin I bought OT. I'd never had one with that X-Bolt safety either. Had a Doe running in at me across the field. I lined up on her and started my follow through, let out half breath, slowly squeezed trigger on my swing, WOOPS! Luckily I thought fast and remembered the safety, pushed it off, still had about a 10 yard shot lane to nail her. JUST got it in her in time. She bounced her head off a big Oak. 240 grain Rem Coreloct and a big Oak tree has some stopping power

As far as the mechanics of the lever gun, if my kid isn't up to the task of operating the action cleanly and safely under all conditions it won't be in their hands at all. And CI, that accident of yours sounds horrid! But you would have to agree that that was a one in a billion way of firing off a rifle. AND it could be repeated with a bolt gun. Limb brushes the safety off and another depresses the trigger. A safety would actually be easier to knock off than pulling a hammer back I would imagine.