They haven't left, they just chum the water a bit and sit back and enjoy the show.

With hard vacuum though, I believe I remember you may get a couple seconds of consciousness before you pass out from the stress. (unless it's explosive which could knock you out instantly) You should usually get a couple minutes without any permanent injuries before death from asphyxiation. Any injuries would more or less be your larynx and eardrums, both from air getting rapidly pushed out. To minimize it you would need to be actively exhaling while opening the tubes to your ears (what you do when popping them) which will allow air to escape less forcefully.

Emboli and frostbite will however happen towards the end of those minutes. But with us being mostly a mix of liquids and solids, (with dissolved gasses) which take time to sublimate, (evaporation in a vaccum) no insta-freeze or red mist.