Since Jesus became a man, His death can only be for the salvation of fallen mankind.

The death of Christ upon the cross made sure the destruction of him who has the power of death, who was the originator of sin. When Satan is destroyed, there will be none to tempt to evil; the atonement will never need to be repeated; and there will be no danger of another rebellion in the universe of God. That which alone can effectually restrain from sin in this world of darkness, will prevent sin in heaven. The significance of the death of Christ will be seen by saints and angels. Fallen men could not have a home in the paradise of God without the Lamb slain from the foundation of the world. Shall we not then exalt the cross of Christ? The angels ascribe honor and glory to Christ, for even they are not secure except by looking to the sufferings of the Son of God. It is through the efficacy of the cross that the angels of heaven are guarded from apostasy. Without the cross they would be no more secure against evil than were the angels before the fall of Satan. Angelic perfection failed in heaven. Human perfection failed in Eden, the paradise of bliss. All who wish for security in earth or heaven must look to the Lamb of God. The plan of salvation, making manifest the justice and love of God, provides an eternal safeguard against defection in unfallen worlds, as well as among those who shall be redeemed by the blood of the Lamb. {ST, December 30, 1889}

Since they aren't lost they don't need salvation. What the cross does is to prevent their defection.

There are some angels who are lost (Satan's hosts, for lack of a better term). Don't they need salvation? They continue to live, apparently forever, since they must be destroyed in the lake of fire, which implies that they do not die on their own, or from old age. (ie: sin does not kill them.)

Didn't Tom post a quote somewhere that says angels benefit from the death of Jesus in a way that saves them somehow?

1.If this logic were valid, it would follow that human beings also live forever (since they must be destroyed in the lake of fire).

2.If death (the second death) is the result of sin, then sin kills them.