The incident unfolded in seconds at the Old City Hall courthouse in room 116.
A witness told CBC News that an officer was just about to handcuff the man and a second prisoner, when the 30-year-old bolted over the witness box.
The man attempted to use a document holder to smash a window, but then went to a second window where an air conditioner was located.
That's when he broke the window and jumped through it.
The man was caught minutes later in front of a nearby bus shelter.
A broken window could be seen from the exterior of the courthouse.