The ultimate goal of our Ismaili friends is to achieve full knowledge of, and consequently unity with, God. As the mirror of God, the Imam is central to this process.
Ismailism is a gnostic faith and so knowledge is at the center of all they do, including reaching salvation. The intellect is the point around which everything revolves, since it is the intellect that is used in the attempt to recognize God.
For our Ismaili friends, recognition of God is to understand God, is to achieve union with God, is to be saved. For each of them, though, the intellect is insufficient since God is beyond comprehension.
Enter the Imam. As the vessel of the Light and image of God and possessor of the Universal Intellect (the knowledge of God as He revealed it), the Imam is the one whom God has appointed to lead mankind to knowledge of Him.
So it is that the first step of salvation is to acknowledge who the Imam is. Secondly, to recognise his role as God's representative. Finally, to submit to his instruction.
Within this framework, there is a certain amount of truth to be found outside of the instruction of the Imam. Our Ismaili friend subscribes to a doctrine of pluralism that asserts there are elements of truth buried beneath the surface of each Abrahamic religion. In pursuing Jesus, therefore, a Christian is held to be not wrong, simply missing the full picture.
A medieval Ismaili author, Abu Firas, wrote a trilogy called 'The Ladder of Ascent' in which he describes life as the struggle of the soul to free itself from the physical world as it draws nearer to the divine light. To arrive is to achieve eternal happiness.
Each of our Ismaili friends will see themselves as somewhere along this process, a process only made possible by an Imam-guided intellect. Salvation, then, rests on the foundation of the intellect and the guidance of the Imam.