In D2:ED as a warrior I stood by one regeneration chamber and just let the walking armours and my creature get in his way, so he tried to make it to the far chamber, but the couldn't do so it before I Rush Attacked him.
Playing a ranger in DKS, this strategy was quite unsuccessful. Not only were the walking armours more dangerous and aggressive, they didn't get in Raze's way, and he could teleport directly into a chamber to heal if is path was blocked. He once even ran to a chamber slouched over while under the effect of a stun arrow. Lancet mentioned he teleported away in the middle of Thousand Strikes, IIRC.
What I ended up doing was (after the conversation) to immediately head around the corner to the first regeneration chamber and hit the lever, then run for the far lever, turn, fire off an explosive arrow at Raze, then jump over the walking armours coming at me to get in a point blank splitting arrow (mostly finishing him off), jumping back and continuing to attack to finish him off.
Basically, just go through to figure out where the levers are, then reload, hit the levers right away and try to do damage as fast as possible (stat/armour boost potions might help, or the Battle Rage skill if you are using normal weapons, etc).
It might help if you just reload a save before the conversation with Raze, and leave him until you are at a higher level or have better weapons and can do damage faster.