Here we describe in detail low energy electron induced fragmentation of a potential focused electron beam induced deposition (FEBID) precursor, π-allyl ruthenium tricarbonyl bromide, i.e. (η³-C₃H₅)Ru(CO)₃Br, specially designed to allow comparison of the effect of different ligands on the efficiency of low energy electron induced fragmentation of FEBID precursors. Specifically, we discuss the efficiency of dissociative electron attachment (DEA) and dissociative ionization (DI) with respect to electron-induced removal of the allyl, bromide and carbonyl ligands. We place this in perspective with a previous surface study on the same precursor and we propose a design strategy for FEBID precursor molecules to increase their susceptibility towards DEA.