These achievements have to be the most difficult I have ever faced. The game is hard enough on legendary without trying to worry how much time I have left (Speedreader). And there’s always some carrier form that gets too close, kills me, and ruins the other achievement (That just happened). How have you guys gotten these? Are there shortcuts or glitches? Before you ask, yes I have bandana on.
This isn’t my video, but RC is really cool and his video helps a lot 
If you look up the 14 minute speed-run on YouTube it’s really not difficult to replicate. Not to mention you don’t die during it, so you can really knock out two birds with one stone.
The Two Betrayals achievements, on the other hand, now those are annoying.
> If you look up the 14 minute speed-run on YouTube it’s really not difficult to replicate. Not to mention you don’t die during it, so you can really knock out two birds with one stone.
The 14 minute speed run he’s talking about is here.
I doubt most people will have quite an easy time of replicating it as Viper Skills though 
You’ve already been linked to my guide a couple of posts up. Thats all the help I can offer.
I tried RC’s way and spent over an hour attempting it. Apparently, the phrase “practice makes perfect” doesn’t apply to grenade jumping.
co-op first on heroic, maybe a friend will help you survive longer, and then for the speed reader, co-op again, and this time have boom skull on (quick kills)