not the same thing, pica gave himself to zoro by becoming bigger, he should have stayed in the caves tricking him
Here King is the one proceeding the attack, pica got attacked by surprise, sneak attack, he wasn't fighting zoro anymore but zoro came with sneak move to catch him offguard, if pica knew he would have went to the ground again before the slice.
King is fighting zoro in this case which is different.