I believe we actually don't know what the guy at the front door did between 1:47 and 2:22 or even if it was the same guy inside the home. It probably took the intruder several minutes to actually find a way into the home, remove interior cameras and roam around before finding Nancy which was likely about 2:22 AM. We just don't know what happened between those two times.1:47am he’s seen at front door
2:22am her pacemaker is out of range of her phone