Continuity mistake: In the beginning when the crew is in the jumper, Ronan Dex has his hair tied back. When they land on the island and walk into the camp, his hair is down, and then they have to run back to the jumper when the prisoners start shooting at them. When they get back in the jumper, Ronan's hair is tied up again.
Continuity mistake: At the end of 2-2, Runner, Weir shows Ronon images of the destruction of his home world - a fact he had been unaware of. But in "Trinity," Ronon says "all these years I thought I was the only survivor."
Visible crew/equipment: After taking the enzyme, Mckay is talking to himself as he dials the gate. When he goes to push the centre button, an arm moves on the opposite side of the DHD. (00:09:35)
Character mistake: Rodney says that one hour in real time would give them months inside the field. This is incorrect because if the ratio of time were 1:250 as stated before, one hour would only convert to 250 hours, which is 10 days and 10 hours.
Continuity mistake: In the scene where Michael is first introduced to his quarters, he goes to pick up a picture of his parents. In the first shot, the laptop next to the picture is closed, but in the next shot through the security camera, the laptop is wide open.
Answer: Those are actually suits that protect from hazardous chemicals. They are cheaper for the prop department and look nearly the same as biohazard suits. A real biohazard suit would indeed have a helmet that seals to the neck.
Grumpy Scot