When Olivia picks up her iPhone to see the picture Lewis sent her, it's shown that the iPhone battery is not full.
But when she unlocks her iPhone, the battery indicator shows that's it's fully charged.
Right before Lewis shoots himself, he transfers the gun to his left hand. When the camera was facing him, his thumb was on the trigger; when the camera shifts a split second later to behind him, his forefinger is now on the trigger.
When Lewis sends Olivia a photo of the girl, the photo is on the 'sent' side of her phone, with her response directly beneath it.
When Lewis brings Benson to the abandoned, run-down warehouse, there is a running air conditioner blowing paper strips.
When Olivia sees Amelia tied up, she introduces herself as "Detective Benson". At this point in the show, however, she is a Sergeant.