Some Model S Sedans Get Assembled In Tesla's Fremont, California Plant
Musk will do this to assure that the particular task is being done in the safest possible way.

As Teslarati explains:

"Tesla CEO Elon Musk has reportedly sent a company-wide email, emphasizing the importance of safety within the Tesla factory in Fremont, California. "Going Forward, I've asked that every injury be reported directly to me, without exception", Musk stated in an email according to a post on the Model 3 Owners Club Facebook page."

That email is reproduced in its entirety above. It comes in response to UAW claims and reports that state Tesla's factory in less safe than the industry average. Musk and Tesla highly dispute these claims.