Scalzi also has the common problem of writing about guns and the military despite clearly knowing nothing about them.

At one point he wrote (apologies for my mistakes, I listened to the audiobook): 'Tagok nodded, picked up the handgun, checked it, loaded it, disengaged the safeties. "This is a Glock 19," she said.'

If you're going to name-drop a specific gun here, you should at least pick one that has a disengageable safety.

A similar problem comes up at the end. The group is worried about facing repercussions from the Canadian authorities until one character mentions that he's an officer in the Canadian military. Up to that point he had been doing a different job because he felt it was more interesting. Now he shows some card to a nearby soldier and we never again hear about problems with the authorities.

I've never been in the Canadian military, but I know that human societies don't work this way. What military allows its officers (even on unique assignments like this) free reign to do whatever they feel like? What government would ignore a dimensional portal and potential nuclear explosion just because one person involved has a higher rank than whoever happened to be stationed nearby?