I’m obsessed with this actually. The canaries were probably so shocked when this happened. Mithrun feels no desires, he never acts on whims, never goes off on his own, never does something other than what he’s told to do.
And now suddenly he’s making a snap decision, going against what he was asked to do, it’s almost like he’s doing what he wants to do. But it’s because it’s what Kabru wants. And Mithrun trusts Kabru.