Frodo goes to Mordor alone because Boromir's betrayal reveals a terrifying truth: the Ring will inevitably corrupt anyone who stays near it, regardless of their noble intentions. In the ruins of Amon Hen, when Boromir tries to take the Ring by force, Frodo realizes that the physical protection of the Fellowship is actually a liability. If a proud warrior of Gondor can fall so quickly, then Aragorn, Legolas, and Gimli are also vulnerable. Frodo's decision is not an act of reckless isolation, but a profound sacrifice born of love. By leaving them behind, he is protecting his friends from the Ring's corruptive influence and protecting the Ring from them. This is visually reinforced when Frodo looks at Aragorn on the banks of the Anduin and backs away, clutching his hand over the Ring; he sees the brief, heavy conflict in Aragorn's eyes before the Ranger yields. Frodo's solitary journey is the only way to ensure the quest's secrecy and prevent the group from tearing itself apart from within.■