It is easy to read the first chapter as a failure of nerve, and every commentator who does so has to explain away the argument Arjuna actually makes. He is not afraid of dying; he is a career soldier who has already fought this war's preliminaries. What stops him is a claim about consequences. Kill the men opposite, he says, and the families they head are destroyed. With the families go the rites performed for the dead. With the rites gone, the ancestors fall. Women of the household are left unprotected, lineages mix, and the whole ordered structure that makes a society continue collapses behind the victory.
That is a dharma argument against a dharma obligation, and it is the reason the book needs eighteen chapters rather than a paragraph of encouragement. Arjuna has correctly identified that two duties he holds are in direct collision, and he has chosen the one that looks more merciful. Krishna will not answer by denying the collision. He answers by relocating the question, first to what a self actually is and then to what a person is entitled to expect from their own actions.
The physical detail is precise and deliberately unheroic. The limbs give way, the mouth dries, the hair stands up, the great bow slips from a hand that cannot hold it, and the skin burns. A man in that condition is not making a considered decision, whatever he says. The chapter ends with him putting down his weapons and sitting on the floor of the chariot with his mind overwhelmed by grief, which is exactly where a teaching has to begin if it is going to be worth anything.