. . .it marks the first time Archer just straight up murders people in order to protect his ship and crew. . .
It's one of my favorite sequences, and I mentioned it in my review thread entry (still need to wrap up Season 2). You can tell what Archer is thinking when he starts asking about exterior access hatches in the Jefferies tubes and orders Reed's team out of there. The cutting between the corridors and the bridge, the mounting tension, the music, and Scott Bakula plays it just right with a decision he doesn't want to make. Then he gives the order.