Being bulletproof has always been something more. Titanium, it's bulletproof. At a deeper level it's due to its intermolecular metallic bonding which means that it's keeping itself together, entire in itself, immune to external momentum.
That's the apex, where you are indestructible, because the isolated you is the entire and complete you, unaffected by external stimuli and momentum. Strong as you are. galvanised against losing control. Just you and only you yet selfless you.