Deliberate mistake: When the ship crashes into the dock, all of the scenes leading up to the crash and after it show a clear view across the harbor as we can see lights and land on the other side. It's not until the ship is about to crash that a thick and dense fog appears and disappears within a minute to mask the ship to create a more dramatic effect.
Deliberate mistake: When Sarah, Ian and Nick are climbing up the cliff with the rope, Sarah is able to easily pull the rope up to place her hand underneath it for a better grip. The rope is quite lax for having three full-grown adults hanging from it.
Answer: Just after she makes the statement, Ian sees the T-Rex outside of the van window and realises that it is going to attack them regardless of the fact that they've returned the baby Rex.