Which first-tier Medic skill does the author recommend?

Resilience, because it helps survive and clutch more than the small flat health bonus of the alternative.

Why Combatant Medic in tier two?

The extra movement speed and ammo help survival, while the alternative speed boost on darts forces the wrong classes to run to the front when the team is moving around.

Which grenade does the author praise?

The Medic grenade, which saves lives more often than expected.

Perks & Classes

KF2 Field Medic Skill Setup: Resilience and Combatant Medic Build

A short build guide from a player who spent most of his KF2 time on PS4 and likes the Field Medic perk skills that often go unused. The setup is not mainstream, but he reports a lot of success with it, especially on Hell on Earth.

Weapons and purchasing

On Hell on Earth the author either asks teammates to "money stack" him on wave 2 so he can afford the Medic assault rifle quickly and pay them back afterwards, or he saves hard for the Medic AR and only buys Medic pistol ammo and grenades in the meantime.
He rates the Medic pistol as an excellent starting weapon, second only to the MP7 SMG.
After the Medic AR, wait a long time before buying the Medic shotgun: it is not really needed until the later waves.

Skill choices by tier

Tier 1 - Resilience. The author takes it every time. It helps you clutch, survive longer and tank, and in his view beats the small 25 bonus health and the over-the-top self-healing of the other option because you can already heal yourself very easily.
Tier 2 - Combatant Medic. Mandatory in his opinion. The extra movement speed and ammo have saved him many times. The other skill in this tier messes up positioning when the team is running around: it makes classes you do not want in front run ahead and sends front-liners too far away. When camping you do not need the dart speed boost anyway.
Tier 3 - Focus Injection. Not because it is super strong, but because Acidic Rounds is weak: it triggers on roughly one in ten ZEDs and does minimal damage. Focus Injection keeps people alive, especially when big ZEDs show up.
Tier 4 - the damage resistance skill. Battle Surgeon is not good enough to choose over it. A 20 percent bonus sounds like a lot but is nothing compared to the life-saving potential of the resistance boost.
Tier 5 - the healing gas skill. An obvious pick; the healing gas is too helpful to pass up.

Extra notes

Medic grenades are the best, they save your life more than you think.
It is easier to heal by waiting for the audio cue (the lock-on sound) than by trying to aim at a teammate.

See also the main perk page Field Medic perk for KF1, and the KF2 guides Field Medic HoE guide and Field Medic loadout guide.

FAQ

Which first-tier Medic skill does the author recommend?: Resilience, because it helps survive and clutch more than the small flat health bonus of the alternative.
Why Combatant Medic in tier two?: The extra movement speed and ammo help survival, while the alternative speed boost on darts forces the wrong classes to run to the front when the team is moving around.
Which grenade does the author praise?: The Medic grenade, which saves lives more often than expected.