Firstly the shot is used to start [Ozymandias] in the flashback when Skyler is packing away the clown she sold.
The shot itself holds so much meaning because of the phone placed right next to the knives. It shows how much different Skyler is and how strong she’s become. Instead of calling for help (reaching for the phone) she reaches for a knife to defend herself and her family from the monster Walt has become.
Interestingly enough, the knife she grabs is the same knife Walt puts away in Season 2, Episode 1 “Seven Thirty-Seven”. [x]
And when you choose a life partner, you’re choosing a lot of things, including your parenting partner and someone who will deeply influence your children, your eating companion for about 20,000 meals, your travel companion for about 100 vacations, your primary leisure time and retirement friend, your career therapist, and someone whose day you’ll hear about 18,000 times.