Should I shoot Hans while he is chasing a player?

No. In pursuit mode he takes about 85 percent less damage and moves much faster, so you only waste ammo.

What should the team do when Hans grabs someone?

Start healing the victim immediately. Each health drain restores Hans' health.

How many times can Hans heal himself?

Three times, according to this guide: after each drain his health returns, then you bring him down to 30 percent again.

How to Kill Hans Volter in KF2: Pursuit Mode Guide

Dr. Hans Volter has crushed many newcomers in Killing Floor 2, and this Russian-language guide (translated here) explains the key point: he has two behaviors, and how you handle his pursuit mode decides the fight. For a different angle on the boss see force Hans to spawn.

Two modes

Normal Hans: he simply tries to kill you.
Pursuit mode: like a cop collecting a bribe, he runs fast after a player and drains their health.

Hans Volter in his official character card Dr. Hans Volter: when he pulls out his guns, stay out of the line of fire.

What to do in pursuit mode

The classic beginner mistake is shooting Hans while he is chasing someone. While he is catching up with a player he takes 85 percent less damage and his speed rises noticeably, so you just burn ammo.

When Hans is down to 30 percent health he starts chasing. Once he catches a teammate and drains their health (the team should start healing the victim at once), his next phase begins.

Hans with jetpack in a gas cloud next to a player Hans inside his gas cloud near a player.

Four phases of anger

Phase 1. Moves slowly, mostly uses melee, shoots his SMG a little and throws the occasional grenade.
Phase 2. Starts throwing frag grenades and gets extra grenades for his gas screen.
Phase 3. Throws far more grenades and can use his jetpack to jump and chase players.
Phase 4. Charges straight at players, mostly in melee but still using grenades now and then.

What happens during a drain

Every time Hans drains health from you or a teammate, his health is restored to 100 percent. Each time you bring him back to 30 percent, he can recover again, three times in total. After that the recoveries stop and you can kill him in peace, although, as many players noticed, you are usually low on ammo by then.

Summary: five rules

When Hans hugs your teammate, start healing them immediately.
Do not shoot Hans while he drains a teammate.
Be careful and run at once if you see him running at you.
Do not waste ammo.
If you are a medic, watch your teammates' health.

Field Medic icon Medics: heal whoever Hans has grabbed.

Meme about Hans: that feeling when you killed all the little humans The author's closing Hans meme.

FAQ

Should I shoot Hans while he is chasing a player?: No. In pursuit mode he takes about 85 percent less damage and moves much faster, so you only waste ammo.
What should the team do when Hans grabs someone?: Start healing the victim immediately. Each health drain restores Hans' health.
How many times can Hans heal himself?: Three times, according to this guide: after each drain his health returns, then you bring him down to 30 percent again.