How to unlock Ammunition Bag (Teacher's Pet)?

[imSHeeP]

Hi,

In the first mission for training, there is a challenge for unlocking Ammunition Bag for a gadget slot. The challenge is Teacher's Pet ("As soon as possible").
I assumed it's about speed, similar to the time challenge; I finished solo in 1:55, but that didn't do it. Can someone clarify what does the challenge entail?

Thanks!

EDIT: Thank you everyone very much for the help! I finally got it, just need to follow the wording literally xD

[Beast King]

In the tutorial there is a spesific place where it acctualy says "bla bla bla.. as soon as possible" Do that thing and you get it ^^

[Raiser]

In case you really want to know:
Arrest the green dummy at the section with all 3 colors beneath eachother!

[Magic]

Going to clarify since the tip was worded weirdly.
When you get to the area where you learn to arrest. arrest the the Green circle. the VERY first one you see when you enter the room.
NOT the one they tell you to shout at!