Psi division

When the Matrix during the Last Great Time War projected the Twelfth Doctor's encounters with Rusty, the Time Lords' psi division investigated the "fascinating" concept that a Dalek could be "conditioned" to turn against its own kind. Even though Rusty's condition appeared to have been created via a radiation-shielding malfunction, the fact that the Doctor was able to have an immediate effect by making direct mental contact indicated to the Time Lords that it was possible that other such Daleks could be created. (PROSE: Dalek Combat Training Manual)