This achievement is for Warzone.
This can be found under Multiplayer -> Warzone -> Warzone again.
To get to Level 5 reqs you have to kill enemies, capture bases, kill bosses and get your team's score up. Level 5 is a fairly common level in Warzone so should appear half-way or near the end.
When it does, an announcer will say the Level 5 reqs are unlocked.
At that point get yourself killed and press
to use req cards. The SAW is a fairly common level 5 card however there are other cards that are level 5 like the Wraith.
If you want to check a cards level, highlight it and press
it should say the number there. Once you use the Level 5 card the achievement will unlock.
As a side note once you use a req card, it will take some time before it loads back up to the top Level.
*Edit: You can also not die and just access a Req store if you are in a base your team controls. They are a big green box that looks a bit like an ATM.