Sure, but that still doesn't explain it. Under the hierarchy, Junior would still be peers with Senior, and they would be under a manager. It's not like each person can only have one person under them.

err no - not in some cultures its like the civil service used to be in the 50's where her where rules about who could have a chair with arms.

Check out workplace on stack exchange a lot of the questions are about friction between juniors and seniors.