According to Osho, Arjuna cannot accept the Divine in totality because the ego’s ultimate fear—annihilation—arises at the threshold. Seeing all beings dissolve in Krishna’s cosmic mouth, he intuits his own dissolution and recoils. Divine realization demands dying while alive: the complete dropping of "I." Clinging to self-preservation, even to possess God, blocks surrender; only ego-death reveals the immortal soul.
He’s scared of disappearing, so he won’t fully drop his “me,” and without letting go you can’t meet God completely.