As soon as he can tell Jack has caught on, there's a new energy in the air that reminds Sinclair of why it's profitable to have a business partner in more ways than just money. And while he's not going to count his chickens yet, he knows he can say with absolute certainty that he would not have gotten this far without Jack. Without Jack, Ryan might still be alive, Rapture would continue it's painstakingly gradual decline and Sinclair would have to suffer through every second of it.

Right about now, Jack's appearance in Rapture feels like providence.

Sinclair picks up the map and holds it in front of them.

"We're here," he says, "that's...there, and..."

He begins walking, away from the desk and past the glass division, mumbling to himself as he tries to match up the blueprint against the room.