Load Mission 4 'Zombie Zoo' chapter 2 on easy with 1 Player zombie settings. Kill the first blind screamer after you exit the safe room. To execute a takedown, we need a 10x combo so that the takedown is ready.
Luckily we can do that with rats and birds and there are a lot of them in this area. After your takedown is ready comes the hard part. In the next area is another Blind Screamer and you have to sneak up behind the Blind Screamer without being noticed
to perform the takedown. If you fail, restart in the safe room and try again.