Puncturing Blow’s replacement effect will exile the target creature if it would die this turn for any reason, not just due to lethal damage. It applies to the target creature even if Puncturing Blow deals no damage to it (due to a prevention effect) or Puncturing Blow deals damage to a different creature (due to a redirection effect).
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.