If an act is morally justifiable by its balance of good and bad consequences and achieves good consequences without non-consensually using anyone as a means, then the agent's intention to achieve bad consequences is morally immaterial to the act's permissibility.
Treating a person as a tool to achieve your goal without their permission or knowledge, rather than respecting them as someone with their own goals and dignity.
Notice, too, that this patient-centered libertarian version of deontology handles Trolley, Transplant et al. differently from how they are handled by agent-centered versions. The latter focus on the agent’s mental state or on whether the agent acted or caused the victim’s harm. The patient-centered theory focuses instead on whether the victim’s body, labor, or talents were the means by which the justifying results were produced. So one who realizes that by switching the trolley he can save five