The assassin cried in despair and utter humiliation as he thought of his carelessness that led to him getting badly hurt by that woman, and now even if he is still alive he would rather be dead than be put behind bars
It is such a humiliating thing for an assassin and a terrorist like him who never fears death to be caught and brought to prison because of a woman. The most humiliating and depressing thing is that he failed to kill the target and even lost the metal bomb he had the dentist planted in his molar tooth
He chose the metal bomb to be planted in his tooth instead of the poison that will kill him. instantly once he bit into it because he didn't want to die alone. He wanted to take the target with him if worse come to worst he would rather take his life taking the target's life with him by making the metal bomb exploded
That way, even if he died in the end, the results will not be that bad.
