Neutral triangle+side square+side square+up square+up triangle. Adds more to that original combo and nets you 140 AP. it can be extremely tricky to do, make sure you're REALLY close when you fire off the Sonic Eruptor. If you do it correctly, your enemy should be really close to you when you initiate the throwing wrench, otherwise your enemy will just get pushed back and you won't be able to fire the Warmonger in time to hit them.
And if you land it, you will almost have an instant level 1. A good thing to do is to run towards your enemy, THEN stop and initiate the combo. If you just stand there and try to do it, it most likely won't work.
RIGHT when you stop walking into the enemy is when you fire the sonic Eruptor, so when you put your thumb off the analog stick (or directional pad) immediately fire. For some reason they won't get knocked back as much and they'll stay close to you during the combo. Hope this helped. This takes A LOT of practice haha