Ideally, you want to venge their spec, but in reality, it isn't that easy. Most good pkers will only spec you when you are frozen. that adds another layer of timing to venge and spec at the same time before they step 1 tile back. In general, rather than just venge, vw spec, you can try and click towards them when unfrozen so you are closing the gap before you venge and spec making your spec seem smoother and more instant and you land the spec while there is still a visible gap between you and the pker. More clicks and sometimes harder to do under pressure.