There is a security guard in the detention area who presses a wall panel to activate/deactivate the force field that secures the detention cell; he does this several times early in the show. On the occasion when Worf and Geordi visit the cell, he presses the wall panel, deactivating the field so that they can enter. Once they step inside, though, the field comes back on all by itself, without the wall panel being touched by the guard. When Worf and Geordi leave the cell, however, the guard touches the wall panel each time like before to deactivate/activate the force field.
Hugh refers to himself as 3rd of 5. When he is finally picked up by the Borg scouts later in the episode, the scouts only seem to attend to three other bodies besides Hugh, who is being transported back with them. However, during his search of the area at the beginning, Worf did report four more bodies, although even then only three bodies were shown. This could simply mean that the fourth Borg was lying somewhere off-screen.
When Riker is assembling an away team, he calls Dr. Crusher and orders her to bring a medical team to the transporter room. However, when they beam down, the only away team members are Crusher, Worf, and Riker. No extra medical team members are present.