While playing in Mayhem 10 with my Fl4k, I have the Slayer Modifier (non boss enemies below 15% health glow and drop shield/health on melee hit). As Fl4k I’m never at melee range, but I decided to test it and on melee hit the enemy instantly dies!
So I decided to try this with Amara and Blitz, and it works great! And also Blitz is refunded since you killed your target.
I only tried this in Mayhem 4, but I’m sure this will work in any mayhem level.