Reapers LB in PvP

Cast 1 time Tenebrae Lemurum and cast another time Communio. PvP is so fast that 98% of the Times a Reaper can't cast this LB fast enough, cause every Player moved already away. As far other Players see a Reaper casting that stupid LB, they jump all on the Reaper and beat the shit out of him/her, before that Spell can be finished. That LB should be a single Cast Spell and not a double Cast Spell.