"Then it is final!" Sceke made one big clap, "Renir will rush into the enemy's base, destroying all their weapons, and then, we will bring out our tanks and bombs. Afterwhich, the release of the Feluxers to go on a rampage-" but he then noticed Renir's troubled face and continued, "To capture all men. The fewer deaths, the better." he said.
If it played out like what they imagined then they will have overwhelming victory. Meaning, they can control who lives and who dies.
Sceke knew that Renir wouldn't kill because that is against his consciousness. This is fatal as Sceke was always concern about Renir's mental well-being. The burden and guilt are too much for someone who doesn't suppress their emotion. Once Renir suppresses his emotions, he will become like Sceke before, aloof on the outside but weak on the inside.
If that is so, he didn't want to kill too. If Renir didn't kill but became a way for a massacre, that would just become hypocritical and ironic.