The pain would be immense. Your skull would hit first as the press lowers. It would slowly bend and shatter while blood begins to seep from your eyes and ears. Then you would start suffocating and spitting blood as your ribs crack and grind into your lungs and heart. You'd finally die at last as your organs and muscles rupture.
Best hope is that it is rigged to just drop or overloaded so that you are annihilated with one blow. Otherwise, pressing is a manner of torture, so this is just torturing oneself to death.
Just guessing, but I'd say definitely not a graceful way to die.