I don't know about the rest if you voidwalkers out there, but it seems like some players are completely oblivious when it comes to vortex effects – they just stand in the area of effect and let their health drain away. I have on multiple occasions gotten postmortem triple downs with vortex grenades, and there are always the guardians that run into the middle of a vortex after a nova bomb.
So to all other voidwalkers out there, do your opponents seem oblivious to your vortex abilities!
To all other players, does this happen to you, or do you avoid the vortex?
Side note: I almost never run into anyone else using vortex, for some reason.