Their "Flesh" died, not the "Soul".
Ge 2:7 And the LORD God formed man of the dust of the ground, (outward man)
and breathed into his nostrils the breath of life; and man became a living soul. (inward man)
Ge 3:19 In the sweat of thy face shalt thou eat bread, till thou return unto the ground; for out of it wast thou taken: for dust thou art, and unto dust shalt thou return.
This is the "death appointed to man", (outward man)
however the "Second death" of the "inwards man" isn't appointed to anyone, Jesus died for the sins of the "WHOLE WORLD".
This second death is the results of "Our unbelief" in Jesus "PREVENTING" him "FROM" saving us.