Other mistake: At first, Ethan tries to board the train by waiting until it slows for a sharp bend. Thanks to The Entity, the train is going pretty much full speed throughout, but doesn't derail or tip at the lower speed sections. In fact, the diners are all blissfully unaware that this is, in effect, a runaway train as they consume their canapés and fois gras, with soft music playing in the background.
Other mistake: Grace crawls across the coal car of the train, and there are several times when she is lying completely prone. In the next scene, there's not a single smudge on her face, hands or clothes.
Other mistake: Ethan (in disguise) throws some gas grenades in the office where the security heads are meeting - there's a massive explosion. Bright green gas fills the room... And everyone working on the typewriters in the room below completely ignores this, despite having a clear view into the glass window/wall of the office above. Even after a couple of minutes of Ethan and Kittridge talking, the phone rings with someone checking on them, rather than security busting in the door immediately.
Suggested correction: The three explosions aren't especially loud. The sound would likely easily be deadened by the walls and windows. The resulting powder (not gas) that's released is only present for a few seconds before dissipating. Since everyone in the typing pool is so focused on their work, it's quite possible it went unnoticed.
