During the fight scene between Gina Carano and Michael Fassbender, the gun between the mattresses can be seen sticking out halfway when he throws her on the bed, but when she reaches for it moments later she needs to dig for it under the mattress.
When Mallory finds out she has a tracker in her backpack, she runs out of the store and across the street into a hotel. As she runs up the stairs she throws a lot of stuff into the stairwell to slow her pursuers. But when the SWAT team comes up the stairs there is nothing there anymore.
When Mallory & Scott are driving, she tells him to have a drink of water in her backpack. She wants some too, but has to have him pour it in her mouth because of an injury to her arm. However, just minutes later while running from law enforcement, she is backing up at a high rate of speed, her bad arm is extended and gripping the passenger seat tightly.