 FACT: Blue suits used in level 4 laboratories have a special air  supply. The sound this makes inside the suit is so loud that you  cannot hear other people. The people at the starting scene of the  movie communicates none the less during the first scenes in the  level 4 laboratory. Yellow suits are pressurized via a small motor  inside it and a set of batteries, but the yellow suits show no sign  of being inflated at all, and when helmets are moved no air rushes  out.