When Sarah Walker shoots the Fulcrum agent, she raises the gun in only her right hand and shoots him. In the next shot, she is seen holding the gun with both hands and the shot is mirrored. When the camera changes, it is no longer mirrored and she is once again seen holding the gun in only her right hand.
When Sarah shoots the Fulcrum agent, it's clearly shown that she has a busted lip and bruises around her left eye. When she goes back into the Buy More to tell Chuck he's safe, which is not long after, she has not one scratch on her face.
Lester is lying down on the stretcher wearing a neck brace and he raises up to kiss Anna. This would not be possible in real life as paramedics always stabilize someone on a back board if the stabilization of the neck with a brace is warranted. The neck brace is never installed without a back board. So Lester could not have done this as he would have been strapped to a back board.