The Emerald Dream was a unique world, a mirror of the planet Azeroth, distinct from the physical world. The sacred tree Darnassus occupied a special plane within the Emerald Dream, a place most Druids could not enter directly without someone to guide them.
The plane where the sacred tree Darnassus stood differed from Azeroth in many respects, including soul, energy, time, and space. Others struggled to distinguish those differences precisely; even Archdruids could not do it.
The Emerald Dream was a world of energy and souls, where it was all too easy to lose oneself and impossible to sense the passage of time.
You might feel that thousands upon thousands of years had passed, while only an instant had elapsed outside.
You might feel as though you had merely had a dream, while ten years had passed in the outside world.
After leaving the sacred tree Darnassus, Shawn followed the guidance of the Soulbinding Staff in his hand, traversed the Emerald Dream's boundless world of energy, and returned to Azeroth.
When he passed through the portal opened by the Elven Great Tree and saw the others, very little time had actually passed outside.
Although he had spoken at length with Archdruid Leral Firefang, in reality, he emerged almost immediately after Broll and the others returned to Azeroth.
Thus, Broll had no idea how long Shawn had lingered beneath the sacred tree Darnassus, nor did he know what had transpired between Shawn and Leral.
Shawn was perfectly calm.
He and Leral had reached an agreement, then signed a Follower contract under the binding authority of the Space Garrison.
Lairal had traded his agreement to "become Shawn's Follower" for the opportunity to return to Azeroth.
Shawn promised that although the Follower contract gave him complete control over Leral, he would never interfere