What's your point? That neither man could kill the other? If so, that's untrue because neither (to my knowledge) are invulnerable, whereas Juggernaut is.
No, my point is, Level 7 is just power that is greater than a certain point. For all we know, Silver Surfer could obliterate Marko because he's power is infinitely better than his durability. We don't know. Level 7 just means big power.