Here’s my thought on that: Along that area of border are buried and hidden sensors that alert the Border Patrol to the presence of people or vehicles making their way illegally north. The Mexican military wanted to abduct this agent and take him south to extract the location of the sensors. Of course, we all know how they would extract that information and what they would do with the agent after they got that information.Each BP Agent has a list in his truck of the assigned number, and exact location of all the sensors in the area. It would be much simpler, and more exact to grab the list, and take it back to Mexico. I've seen the lists, and see agents using them regularly.