The Terrigen Crystals and Mist give superpowers to those with Inhuman lineage, but kill anyone else they come in contact with. When it was released in the ecosystem in the fish oil supplements, there should have been biotransformations and fatalities, but none of the latter have been reported yet.
Actually, the crystals themselves, as explained my Skye's mom, only affect inhumans. It's the outer metal shielding of the Diviner that is lethal to regular humans. One of the main characters was killed in the temple after the shards had stabbed him. Skye's mom's crystals had contained the metal since she had been unable to leach them after melting down one of the diviners. However, as Morse explains in the third season, the crystals melted in the water, leaving the metal behind, making the fish oil inert to all, except of course, the inhumans.
Actually, the crystals themselves, as explained my Skye's mom, only affect inhumans. It's the outer metal shielding of the Diviner that is lethal to regular humans. One of the main characters was killed in the temple after the shards had stabbed him. Skye's mom's crystals had contained the metal since she had been unable to leach them after melting down one of the diviners. However, as Morse explains in the third season, the crystals melted in the water, leaving the metal behind, making the fish oil inert to all, except of course, the inhumans.
The piece of parchment that Fitz takes out of the scroll has noticeably darker writing on it when he handles it as compared to the close-up / POV shot the audience get to see moments earlier.
When a hospital security guard has a hole blasted in his chest, the hole does not appear until after he's slumped to the ground; the hole can actually be seen fading into existence.
The interior of the DC Metro train is not correct...none of the cars in service at the time had bench seats along the walls. You can see in the exterior shot that was actually filmed on location that the seating arrangement does not match.
During the fight / breakout scene in the subway Coulsons missing hand is suddenly on his right, instead of the (correct) left, while he punches the goon in the face.
It's a common mistake in Joss Wheadon's works. The most blatant is in "Buffy the Vampire Slayer", when vampire Spike's motorbike suddenly becomes AHAMAY instead of YAMAHA.