Goofs

You cannot use defibrillator around the neck and clavicle bones.

Locating the stolen phone will not give the floor number of a multi-story building, only the building location itself.

Whilst it is laudable to show ASL it's simply not realistic that anyone can learn more than rudimentary signing in eleven months. It takes literally eight or more years to achieve fluency.

But here the whole point is that he isn't fluent, and only has a rudimentary grasp of the language, which can easily be done in a couple of months.

Frank texts Doug for help. Doug calls him back and, instead of texting Doug and saying that he can't hear, Frank gets Ava to read Doug's lips on the Facetime connection. Frank should be texting anyway so that the killers can't hear him.