But they shouted (oi de epepwnoun). Imperfect active of epipwnew, to call to. Old verb and a verb pertinent here. They kept on yelling. Crucify, crucify (staurou, staurou). Present active imperative. Go on with the crucifixion. Mark 15:13 has staurwson (first aorist active imperative), do it now and be done with it. No doubt some shouted one form, some another.