He tells you it's going to kill you and has no reason to lie. Shepard has every reason to believe him.
Maybe
you do. Still doesn't provide any reason to intentionally blow yourself up.
He
implies you would die, versus, say, Control, where he says you would in as many words. Is that a reason to blow yourself up and guarantee it? That's like shooting yourself because a doctor walked up and said you had cancer - no questioning it, no second opinions, just whip out a pistol and end it on his word. Does that make any sense to you?
Do not let this be misconstrued to think I pick Destroy solely because Shepard has a chance to survive it.