I think we come in contact with the Blood of Christ through faith.
“Most assuredly, I say to you, he who hears My word and believes in Him who sent Me has everlasting life, and shall not come into judgment, but has passed from death into life” (John 5:24);
“Most assuredly, I say to you, he who believes in Me has everlasting life” (John 6:47);
“Whoever believes that Jesus is the Christ is born of God” (1 John 5:1).
Imagine the situation of a person who came to Christ through faith and then was killed before baptism could be made. Even the Roman Catholics, I believe, consider that faith in Christ and true repentance will allow one to be saved at or near the point of death. And they understand baptism to be effectual in and of itself.
(RC friends, help me out here.)
I, nor anyone else, can say what God will do in such "hard cases" as you mentioned in the last paragraph. It is not for us to decide.
It is important that we understand that scripture must be looked at as a whole, and not just verses here and there. There are verses that teach belief or faith leads to salvation. There are verses that teach that repentance leads to salvation. There are verses that teach that confession leads to salvation. There are also verses that teach that baptism leads to salvation.
I ask you one question: Do these verses contradict one another, or do they as a whole, teach all that is needed to accept God's gift of salvation?