The story's getting better.
A few random comments:
The robot has captured my heart.
We finally have the story about the chip Kal's been carrying around, although I suspected it to be the reason Tinker's been after them.
It has never been explained how old these kids are. I'm just assuming they're kids because they look and sound like teens.
The military is the bad guy because they're always trying to cover something up. They have secrets that they would kill anyone to protect. Their motto, "kill first, ask questions later" is enforced, even when dealing with the robots. My guess is the kids will probably befriend one and become the peacemaker.