"This is the limit! Now, I'm in for it." For a few moments he crouched close to the boathouse nearly paralyzed with fright.

His consternation increased when a sound over by the fence indicated that the policeman was trying to mount that barrier.
Now, Fred's courage returned, or enough of it to enable him to try to escape.

Bending low, he turned and ran swiftly, almost noiselessly.

His speed astonished even himself.

He gained the corner of the fence by which he had entered the yard.