Ah, an semi-unanswered debate -- do all roads lead to Heavan, since Christ's sacrifice is so large?
The most risk-adverse answer, reading the above passage in context, is that, to avoid Hell, one must: (1) believe Jesus Christ died on the Cross for your sins and (2) accept and acknowledge that free sacrifice to you (and sincerly accept the changes that go with accepting such a gift --- that's my part, it's not expressly in the Bible).
This prayer should do it: "Dead God, I believe you sent your son, Jesus to die for my sins so I can be forgiven. I want to live the rest of my life the way you want me to. Please put your Spirit in my life to direct me. In Christ's Holy Name I pray, Amen."
There are interpetations similar to yours, that acceptance of the gift is not even necessary, and while I like the thought, I am increasingly inclined to believe such hopeful interpretations to be incorrect.