How was Max Kale able to obtain Walker's truck mobile telephone number? It seems that number would be secure and known only to the Texas Rangers and other key support staff.
Max Kale had a large detonator with #1-4 and switches for each. Each switch blew up a house. However, more than 4 houses continued to blow up one by one still showing the same detonator.
The "neighborhood" on Rodney Lane was supposedly where Max Kale grew up. However, that "neighborhood" is far too new for him to have grown up there.
The "neighborhood" on Rodney Lane was obvious it was situated far from any other houses that could be damaged from the multiple explosions.
It is not revealed or shown how Max Kale is able to surreptitiously plant the explosives that demolished the homes when detonated by remote control in the finale.