You did the same fail I did in the first try.
You are not supposed to click on the toolkit and then on the turret.
Go to the turret with the toolkit, stand next to it, select the turret and then change it into whatever you can. It's like you are a engineer except not all 5 turrets are available to you. Try it out, then you know what I mean.
I remember back in 2015 when the Agent was op... Rest in supplies, my friend.