Which two phrases convey unease in the excerpt?

excerpt adapted from The Count of Monte Cristo
by Alexander Dumas

The dock was soon covered with the usual crowd of curious onlookers, as the arrival of a ship is always a great event in the town of Marseilles. This was especially true when, like the Pharaon, it has been built in the city and belongs to a local shipowner.

Meanwhile the vessel was approaching the harbor, but so slowly and with such an air of melancholy that the onlookers, sensing misfortune, began to wonder if an accident happened on board. However, the experienced seamen among them saw that if there had been an accident, it could not have happened to the ship herself, for she had every appearance of being under perfect control.