If the case were prosecuted in a court of law, the mens rea would apply to the Roman guards and possibly the Jewish leaders.
This is perhaps a little easier than you might think:
Ask yourself: who administered the lashings?
Who drove the nails?
Who pierced his side with a spear?
Irrelevant; the question we are examining is suicide — and we have a confession:No one takes it [his life] from me, but I lay it down of my own accord. I have power to lay it down, and I have power to take it up again. I have received this command from my Father.
The question of murder is discretely separate; the two can coexist as well as independently exist.
This is perhaps a little easier than you might think:
Ask yourself: who administered the lashings?
Who drove the nails?
Who pierced his side with a spear?
All irrelevant to the question of suicide, unless you can prove that one cannot commit suicide by surrendering to the actions of others which the one in question knew beforehand would result in his death.