Killing gauge for the 0-brane on AdS₂ times S² coset superspace

How to gauge fix $\k$-symmetry for the super 0-brane action on $AdS_2 \times S^2$ in Killing gauge properly is discussed in order to find the superconformal mechanics which describes super 0-brane probes moving on $AdS_2 \times S^2$. The dependence on the coordinate frame for the proper Killing gauge is considered and the subtleties of gauge-fixing $\k$-symmetry in Killing gauge are analysed explicitly. It is found that the Killing gauge works indeed without the imcompatibility if the magnetic charge of the super 0-brane is nonzero.