All along the film was self-explanatory but it seems the latter part is conveying something else. At the beginning and during the entirety the viewers can see the desperation in the face of the man, who upon learning that the virus can't be contained proceeds to go up the topmost part of the big ship and plans to take his own life. One can see the great number of ships nearing an island but the last scene will take you by surprise, as the man was actually in a convalescent home. The aerial view with the island along with the ships surrounding it reminds one of the microscopic cells earlier seen by the man. This leads us to think that all of the earlier scenes were just in fact all a part of the figment of the man's imagination. Mind-boggling but very engaging, do check out this film.