The Doctor is In

The Doctor is In is a Zombies related achievement in Call of Duty: Black Ops 4. It requires the player to use the perk PhD Slider to fall 10 feet and kill 10 zombies with a single detonation of the perk's explosive effect. In order to help unlock the achievement easier, it is recommended to have PhD Slider as the Modifier perk, as one of the perk's modifier effects allows the player to have increased explosive damage on enemies when entering a slide from a greater height.