The reason it’s missing is because they never were given the choice to partake. As soon as they were “caught” the Lord said, “…Behold, the man is become as one of us to know good and evil; and now lest he put forth his hand and partake also of the tree of life, and eat and live forever, Therefore I, the Lord God, will send him forth from the Garden of Eden, to till the ground from whence he was taken” (Moses 4:28, 29). If they were given the choice, then the Lord’s word (that they would die) would become void, which, of course, couldn’t happen. “For as I, the Lord God, liveth, even so my words cannot return void, for as they go forth out of my mouth they must be fulfilled. So I drove out the man, and I placed at the east of the Garden of Eden, cherubim and a flaming sword, which turned every way to keep the way of the tree of life.”