A Deus challenge here for folks - especially folks with go pro cameras

Here is the challenge.
Put together a booby trap scenario using nonferrous item and ferrous (use whatever you desire and how much) where using Deus in reactivity level 4 will detect and reactivity level 3 won’t.
With silencer set to level minus one. With all other settings in whichever program is used for comparison left the exact same.

The why behind this???
I’ll let folks guess.