The return journey for the tank

The portable aquarium had to be returned empty after the school demonstration. The access lift was out of use, leaving a flight of stairs between the hall and the loading area. Its handles were recessed, making the tank awkward to grip with the protective gloves on. The empty container was lighter but still too wide for the trolley we had brought. A door halfway down the route would not stay open by itself. Meanwhile, the caretaker needed the hall clear before the evening class arrived. We called for additional help rather than trying to carry it down alone.

Describe the difficulties of returning the empty aquarium. You may support your points with brief quotations.