Corrected entry: Roxy would need more than a Halo Suit to survive at that attitude for such a long time - she would freeze to death.
Corrected entry: When the barracks are completely flooded, Eggsy breaks the two-way mirror with his fist, and only a few hundred gallons of water pours into Merlin's observation room, spilling the trainees onto the floor. A moment later, the floor is merely moist, and Merlin is apparently dry. If the watery contents of the barracks (flooded 9 feet deep) had suddenly gushed through the window, it would have completely flooded the observation room to several feet in depth in a split-second, and with lethal explosive force.Charles Austin Miller
Corrected entry: When Eggsy visits Galahad in the hospital (first time you see Galahad awake after the coma) Merlin comes in to show Harry the replay of the professor's head exploding. Then they watch Valentine's "free Sim cards for everyone" conference and Harry notices that Gazelle also has a scar on her neck. Close to the end of the film, when Merlin blows up everyone's heads, Gazelle should have too.