Some are more hands on though and prefer social learning ("show me how to do it..."). To each their own, but I personally learn faster when left alone than when someone tries to put me through their "course".

That being said, just reading the source code is under untilized these days. Engineers sometimes ask me how the system works, I send them to the repo. It's all right there, just have to learn to read the story it tells.

One risk is that often times the co-worker knows the business logic in "how it ought to be" not the reality of the underlying code. I've had engineers say "It works like X" and I have to say "well, only sometimes. The code says this..."