Lousy editing when the acid burns through dude's sunhat.
When Valentine (Chris Potter) tells Mercer "Just help me get these people out of here and I'll come back with you" around 51 minutes in, Mercer (Alex Reid) opens her mouth to reply but only the voice of the doctor (José Sancho), who had just walked into their perspective, can be heard, making it sound like Mercer is talking with a man's voice as no audio whatsoever is heard coming from her mouth.