I do not agree with some critics of the film as I found it aiming for and largely achieving the profound.
I believe the film is an allegory for 'end of the world ' or at the very least the end of the current world order.
The film maker is drawing upon the hopelessness of the character's situation, confined in a luxury world but being unable to enjoy any of its luxuries, being within but apart from it, filled with hope then despair, desperation plunging to the depths of survival instincts , the fight to maintain sanity, and the underlying fight to escape.
Destruction and re-order to follow.
This feels poignant at this time in our history.