Well, the stupid continues for another season.
Somehow, all the characters miss the obvious, that a pregnant women shouldn't manipulate a strange alien machine that arcs strange radiation through her fingertips.
Too bad Tom didn't read up on his TV Tropes before the Internet went down, or he'd have known that, when someone says he's narrowed down the list of suspects, but it's not really important and can wait, he's wrong and he's going to die.
Gotta love how the Mechs just left the front gate open, and didn't come back once the main attack was under way.
And the cherry on top: Hal can sneak out of the city, and no one spots him, even though the perimeter's supposedly secure, oh and any guards who might notice him at any point will also notice that he's walking and without his wheelchair.
Can't say I really care anymore.
The reason that the front was left unguarded is so that they can simplify the action and minimize the human casualties. Even with the Volm weaponry the humans should not be winning at this point. They've established that the Volm are nothing but a beachhead force.
But yes, wanting to have Hal physically unfaithful isn't enough reason to trash willing suspension of disbelief. You have to contradict the stated facts of the situation as presented to accept that Hal actually got outside without being detected, not just once, but repeatedly. Even if that woman sleeping with him is stoned every night!
However, the benefit the Volm receive from Earth may be a killing ground for their enemies. Also, it is highly unlikely that the humans will ever be able to exterminate the skitters. It's not even certain they should want to. Humans have cards to play against the Volm if they should want more than a battleground.