Texans play absolutely awful situational football. Get no pass rush. Bite on PA when the Hawks have no running game all day. Trust their porous defense to get the win instead of getting a first down on offense to ice it. They played to lose and let the Hawks luck back into it.
You see this happen all the time with the Hawks and Pats. Teams put themselves in bad spots and let them backdoor their way in. It's not necessarily the Pats and Hawks outsmarting everyone else, it's just everyone else being really fucking stupid. The Texans were rock stupid today. Good coaches give their team every opportunity to win. O'Brian just gave the Seahawks the opportunity to win instead of his own team, and everyone saw it coming. Of course the Seahawks would march down and get that TD.
Coaching in the NFL really makes you shake your head sometimes.