"it was going to and fro instead of returning back to the ark for rest or safety" That's one way of looking at it. I understand it went to and fro because its mate was on the ark and being an unclean bird only one pair of them was on board, as opposed to 7 doves. The bird left a short distance to obey Noah but returned back quickly to check up on his mate in the ark then want back out again. When Noah sent a dove it just went straight out.