Abraham attempted to "save the righteous" in Sodom. The problem is that there are none righteous, as demonstrated by scripture.
Rom 3:10-18 (AKJV/PCE)
(3:10) As it is written, There is none righteous, no, not one: (3:11) There is none that understandeth, there is none that seeketh after God. (3:12) They are all gone out of the way, they are together become unprofitable; there is none that doeth good, no, not one. (3:13) Their throat [is] an open sepulchre; with their tongues they have used deceit; the poison of asps [is] under their lips: (3:14) Whose mouth [is] full of cursing and bitterness: (3:15) Their feet [are] swift to shed blood: (3:16) Destruction and misery [are] in their ways: (3:17) And the way of peace have they not known: (3:18) There is no fear of God before their eyes.
God, being the author of Life, has the right to take life at His will. That is NOT murder. Everyone, save the Lord Jesus Christ, deserves to die.