During the shoot out in the hotel room, Ryker is using a revolver with a sound suppressor. A sound suppressor is absolutely useless on a revolver, since the muzzle gases leave already at the gap between the drum and the barrel, hence a bang is already audible.
At the airport, the agent tells colt and Howie that Ryker got on a plane for Hawaii, but when Colt is on the phone with Jack, he tells her that Ryker has left the country. Hawaii is a part of the U.S., so he did not technically leave the country.
The whole Hawaii adventure makes no sense. All Jack needed to do was have a message delivered to the guys on arrival in Honolulu informing them that the assignment was over and to fly back. All the ensuing intrigue would have been preempted.