With each word, with each sentence, you can see where the seemingly inevitable doom might have been averted. If there were tenderness in “I did love you once” it might be answered with tenderness, with “I loved you too” or “Don’t you still?” or “What happened?” or “I know.” Instead this line is both an acceptance and an accusation, that somehow Hamlet had been lying, had been manipulating her, that their relationship was all an elaborate hoax.And with this point of view, Hamlet can then accept that proposition, having been cast as a manipulative villain, he proceeds to really play the part. And the fact that he may be aware that he has an audience might heighten that effect significantly. The show always gets more intense when someone is watching.