I too was sobered by the film you saw, and I don't think anyone could come away from it without being deeply moved. As the Gospels make clear, Jesus was innocent of any wrongdoing but He refused to escape or take another path.
Why did Jesus willingly die such a violent death? The Bible says He went to the cross for one reason: to become the final and complete sacrifice for our sins. We have sinned and are guilty before God, and we deserve to die for our sins. As the Bible says, "There is no one righteous (or free from sin), not even one" (Romans 3:10). God is holy and just, and sin must be punished.
But Christ became our substitute. We deserve to die for our sins but He died in our place. He was without sin but all our sins were placed on Him, and He willingly took the punishment and death we deserve. The Bible says, "For Christ died for sins once for all, the righteous for the unrighteous, to bring you to God" (1 Peter 3:18). Christ died for you!
Why did He do this? He did it because He loves us and He wants us to spend eternity with Him in heaven. The Bible's words are true: "For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life" (John 3:16). Have you responded to His love by giving your life to Christ?