The Bible claims Pilate marveled that Jesus was already dead late on the afternoon of the crucifixion (Mark 15:43-44).
Mark 15:43 Joseph of Arimathaea, an honourable counsellor, which also waited for the kingdom of God, came, and went in boldly unto Pilate, and craved the body of Jesus.
44 And Pilate marvelled if he were already dead: and calling unto him the centurion, he asked him whether he had been any while dead.
Here is the greek word for"marvelled" in the KJV.
Mark 15:44 And Pilate marveled if he were already dead: and calling unto him the centurion, he asked him whether he had been any while dead. 45- And when he knew it of the centurion, he gave the body to Joseph.
Why? Pilate had Jesus scourged (John 19:1) with a full Roman scourging...
Then Pilate, therefore, took Jesus and scourged him.
Pilate saw him in person after that (John 19:5).
Then came Jesus forth, wearing the crown of thorns, and the purple robe. And Pilate saith unto them, Behold the man!
Based on what I have read about a Roman scourging it was not uncommon for a person to die during or shortly after a Roman scourging
Pilate knew what shape Jesus was in. After all, he saw him AFTER the scourging. It was possible for someone in reasonably good shape to survive a crucifixion for two to three days but Jesus was beaten to a pulp and died a few hours later. So why was Pilate surprised? Jesus was no doubt greatly weakened, probably fatally, by the beating itself. So, why was Pilate surprised?
The crucifixion itself was a horrible way to go.