He fears that if he remains in the room he may have to open it again, and that Mrs. 168 Inglethorp might catch sight of the letter before he could snatch it up. 
He is afraid that, should he stay inside the room, there is a chance he might need to open it once again.
He is not at all afraid of remaining in the room and opening it again.
Some slaves were freed if they offered their services.
The little boy is playing.
People stand in line at the airport to go through security.
People playing on the beach.
A guy holds a basketball.
How long should we talk for?