How can I describe an examination room from the perspective of a clock on the wall?
I think the essay should be rather creative writing than a research paper. This means you are free to use lots of literary devices, which I strongly recommend here, such as analogy, metaphors, epithets.
Write as if you look with the eyes of the clock and describe what you see. For example, you may start telling that you have spend a long dark night investigating the shadows, now the light came into the room lightening 3 (4,5) long rows… As I mark the ninth clock, fist students start to come in – some head confidently to a definite place, some look around being unsure what place to choose.
Then, you may describe how the look of the students changes from the beginning to the end of the exam. Some of them may look concentrated, some – lost and desperate, nervously biting their pens. Therefore, finish with how students leave the room.
You may write the core of an essay and I might help adding some creative details when editing your essay.