Walter White is working for Gustavo Fring and as time goes on, Walter is doing things that start to piss off Gus. You don't want to piss off Gus as he doesn't take too kindly to people crossing him. Anyone other than Walter would have literally bitten the bullet a long time ago but Walter is not just anybody, he is special and is able to produce something that nobody else can, so Gus has to bite his tongue until he can find someone who can learn from Walter before taking him out or at least attempt to. So Gus asks a couple of people to study Mr White and learn his secret so he can dispose of Mr White