Ghostwheel
Pyrrhonist
Think of it this way:This seems backwards - getting in his car and driving around before looking on foot around their home.
"As soon as I seen they were gone, immediately jumped in the car and did all the dirt roads, all the culverts, checked over the rivers and streams. As soon as I got home 10 minutes later, I headed out on foot.”
"As soon as I seen they were gone" in my mind means "As soon as I checked the house, yard and nearby surroundings and saw they weren't there (gone)" then he immediately got in the car to look in places that they might have gotten too and maybe could not get out. Maybe places they could have easily ended up if swept up in the river. Making sure they aren't in water would be a priority, I would think. Like swept into a storm drain.