Let the gentleman with 8 soak shine as it stands. He has spent significant character resources in becoming indestructible, and as such should be allowed to have that be their forte. Let them tank small arms fire with impunity as they have not spent those same resources on being able to Charm or Coerce themselves out of difficult situations. Continue to use reasonable threats, eg threats that do not present a significant danger to Mr Soakity Soak, but are reasonable threats to the members with 3 soak, blaster pistols and/or rifles as the case may arise. Sure he'll be the last man standing, but usually that is a sign to quit stabbing things and surrender so the other characters can rejoin in the next scene/encounter, either that or the tank has to deal with hefting everyone to safety all by his lonesome - hilarity ensues.
TLDR: You wouldn't panic if the Face was able to Charm/Negotiate out of the most ridiculous situation, why are you panicking about the tank tanking ridiculous damage.