Walter is visiting the Lab, Gus makes the offer. Walter says no. Is he dead?
Actually, no. Gus wasn't going to kill Walter...yet. There are two main reasons for that:
1) Walter IS Heisenberg and he owned the recipe
As you recall, Walter (aka) Heisenberg created the recipe and only he (with the assistance of Pinkman) could do the product. But Gus Fring knew this and was conscious when he showed the lab to Walter but at the time, Gus had another thing on movement because as you can imagine, Walter wasn't the first choice.
2) Enter Gale Boetticher the Candidate
Gale Boetticher (aka) Shotgun was the first and the mandatory option for Gus because, unlike Walter, Gus knew Gale years ago and like Walter he is super prepared to do the job, with a MS degree in organic chemistry and a specialization in X-ray crystallography. He was the main (and only) candidate to run the lab and in fact, Gale assembled the SuperLab but he explained to Gus in the S04E01:
Sir, I can guarantee you 96 percent. That figure, it's hard-earned, 96. And I'm proud of that. However, this other product has 99 percent.
For Gus (as far as I can see) it is just 3% margin, something acceptable and also recall that Walter White (aka) Heisenberg is not someone who can trust and have too much considerations but Gale insisted:
(...) And look the place you built, the money you're investing (..) and I know you want the best.
So, when Gus showed him the lab, he wouldn't kill Walter...yet. The possible plan that Gus could consider is:
- Walter showed Gale how to prepare the perfect-99-percent pure meth.
- Gale notify Gus that he is ready enough too cook the meth (99% pure) by its own means.
- Gus kill Walter