Just look at how this guy's hand is easily out the window. If he put his other hand in roughly the same place and pulled himself forward, would his eyes go past the window sill so that he can look directly down? It sure looks to me like he could do that.
Furthermore, I only just noticed that the angle of the windows works in favor of performing such a feat. We have seen how it is precisely 17" from the back of the railing to the window at the height of the top of the railing. But the glass is angled back toward the viewer, so the distance you need to extend would be shorter, because the window sill is closer.