Minato leaves the office with his wife pregnant and ready to give birth and Hiruzen returns with a screaming infant and no blood on his clothes.
(one hokage dead is one too many)
Minato leaves with a smile on his face, excited and terrified in turns and Hiruzen returns with an ache in his bones, all too tired and all too sad.
(age has a tendency to catch up to you)
Minato leaves with his wife alive and Hiruzen returns with his wife dead.
(no body recovered)
Minato is
(but then he isn't)
Hiruzen isn't
(but then he is)
Hokage.