Panzer Soldat is a special zombie in an armored suit that runs after you. He has a guaranteed spawn on round 8*. He is very dangerous so I would recommend having Juggernog. Staminup would also help. I would also suggest to do this near the end of a round if possible.
One of his attacks is he launches a claw at you and pulls you towards him if it catches you. He does this often when you are running away from him. If he grabs you with his claw, you have a short amount of time to break free before he downs you. To break free, you need to shoot his arm.
Assault Rifles, Sub-Machine Guns, Ray Guns, etc. are very good for this achievement. It is possible to break free with your starting pistol, so don't worry too much.
Once you have freed yourself and a teammate from his claw, the achievement will unlock.
*Thanks to SinistrBetrayal for the spawning tip.