This doesn't tell us anything new about the jailbreak, it's entirely about the baseband unlock. This is one of many steps needed toward unlocking the baseband.
As far as the jailbreak, we already know that MuscleNerd can execute arbitrary code on the 4S. What we don't know is whether the exploit he uses is close to being (or even can be) made into an end-user jailbreak. We also have no idea if such a jailbreak would be tethered.
I agree with others who have guessed that they won't release a jailbreak until they've perfected a downgrade path. For one thing, they are currently as helpless as we are should they have to restore their own 4Ses -- making it pretty dangerous to test a jailbreak that might break their OS and render their personal 4Ses unjailbreakable.