Arlington Road: Example of a "Moment"

Here is an example of what James Stewart meant (I think) by a "moment". See my post  http://capeldunn.blogspot.fr/2013/04/moments.html

If you saw the movie Arlington Road some time ago, here is a summary of the first part of the film, taken from Wikipedia. The last paragraph, in blue, corresponds to the clip from the film shown below. I wonder how many other people found this seemingly innocuous extract actually the most terrifying scene in the whole film?
A "moment" if ever there was one!

Michael Faraday (Jeff Bridges) is a college history professor at George Washington University who has been raising his nine-year-old son, Grant (Spencer Treat Clark), since the death of his FBI agent wife, who was killed in the line of duty in a scene loosely based on the real-life Ruby Ridge incident. Somewhat of a specialist regarding American terrorism and due to teach a class on terrorism at the university, Michael starts to become suspicious of his new suburban neighbors, Oliver (Tim Robbins) and Cheryl Lang (Joan Cusack), whom he's just met after taking their son, Brady (Mason Gamble), to the emergency room following a reported fireworks accident.

At first his suspicions are based on little things such as Oliver's architectural blueprints that seem to be for something other than the shopping mall he claims he's building, as well as pieces of mail that contradict where Oliver said he attended college. Neither his girlfriend and former student, Brooke Wolfe (Hope Davis), nor his wife's former FBI partner, Whit Carver, believe any of his wild theories. After doing some digging, Michael discovered that Oliver's real name is William Fenimore, and that he built a pipe bomb and used it to blow up a postal office in Kansas when he was 16. William/Oliver confronts Michael over his looking into William's past. He reveals that 'Oliver Lang' is the name of his friend, who died in a hunting accident. William's family had owned a farm but it went broke because the government 'appropriated' the river that ran through it 'for other uses'. As a result the crops died and they could not raise any animals. William's dad then killed himself and made it look like a tractor accident so the family could claim the life insurance. He left a note for William explaining everything. He built the pipe bomb to get back at the government. When William's friend Oliver died he took his name the next day to hide his past. This makes Michael think twice about what he had found out.

Michael continues to uncover what could be possible evidence and becomes even more wary of Oliver and Cheryl. Michael's girlfriend, Brooke, casually spots Oliver and follows his car after witnessing a suspicious package delivery in a garage. Her trail ends up in the headquarters of a mail delivery company from where she decides to call Michael and leave a message, finally accepting his fears as founded; unfortunately, after hanging up, she turns around and stumbles on Cheryl, who had obviously heard the whole message.

And here is the clip:

https://www.youtube.com/watch?v=O6ZWqQ53cJM