How Dimeric selenium chloride undergoes disproportionation reaction?

Dimeric selenium chloride (Se2Cl2) undergoes disproportionation reaction in the presence of water to form selenious acid (H2SeO3) and hydrochloric acid (HCl). This reaction involves the reduction of Se4+ in Se2Cl2 to Se2+ in H2SeO3 and the oxidation of Se4+ to Se6+ in HCl by water.