When Catherine opens the door for the first time, one can see she has the Nazi's notebook in her hands while in close range. When she's saying "that's it", and walking to her friends, her hands are now empty.
When Catherine plunges her face into the event horizon, her hair goes from hanging down next to her face to, inside the event horizon, being pulled forward. This is a result of the fact that the effect is filmed with Ellie Gall bending downward to put her face into a pool of water.