its not lethal i tested it myself in lobby some time ago. i think its better call new trick that allow to counter shiv(i am shiv main). so as i understand shiv passive stores damage but its remembers source of it, so pure pocket ult will not kill him, more intresting part, if shiv get enough damage from gun or other abilities damage from pocket ult and other damage mixes, so active part of shiv passive will clear part of other damage and part of pocket ult damage. so if in delayed damage shiv still has other damage, then he will die, else he will not, intresting interaction, but really hard counter to shiv
