That was a poorly directed episode. There were a lot of parts that leave the viewer questioning why the characters were acting that way. The worst part was when the soldiers shot a faker parasyte's arm, let it run away for some inexplicable reason, only to chase it two seconds later, shoot it like crazy, let it run off again without confirming the kill, and then allow it to meet with our big bad. Wow, that was horrid. It reminded me of the first episode of Seiken Tsukai, which I dropped after finishing.

The only other thing that made less sense was a bunch of soldiers following an obvious parasyte to an open room. Sure, it wouldn't have made a difference if they fought in the hallway, but they didn't know that. If anything, it reeked of a trap, but for some reason, they all just followed along like good little kids.