IT KEEPS IT INTERESTING
to do this one you have to... kill someone with your primary then secondary then use your streak something like overclock then kill someone then while mid air then while sliding.

HOLISTIC MEDICINE
for this one go on siege under and keep going until you reach the elevator part where you have to activate the power, instead of going forwards go backwards until you see a dead scientist then simply crouch on him until the achievement pops up.

DODGE THIS
make sure you have phoenix blade after you get phoenix blade go to the foundry map and get some kills till you have it then simply wait for the lava to fall while it does activate your thing and jump into the lava, im not sure if you'll get it as i somehow got it as medic using overclock.

OVER HYDRATION
make sure you have completed explosive results to get the wiggs skin as you'll need it heres a example where to go after you go here or close to it crouch and look down as much as you can, then wait a few seconds and you should die.

STICK TO SALAD
become tank then go to the caves map and block the little water thing for a few seconds until the achievement pops up.