I do not think ”Poirot watched him narrowly ”"that you quite realize the unfavourable nature of your evidence at the inquest. 
Poirot was focusing on him carefully.
Poirot dozed off and no longer held his attention to him.
John was about to show a room.
Grab me, come here and grab me.
The rate fluctuated no matter what I did.
A woman is falling down stairs.
Peter said it was from the roof.
Many places offer you exercise breaks during the day.