Purple doors usually make an error sound when you try to bring an item through them. However, there is one particular door that says something different. Near the end of the game, reach Floor 5 of the Tower. You will encounter a puzzle that requires a mine to destroy a killer turret to progress. After the turret, place the fan parts and use a crate to activate a floor button. Collect the Jammer device, and fly to the area above it. Use the recording device twice to get through both energy fields. Keep the Jammer and continue to a purple door. Have any item, such as the Jammer held as you try to walk through the purple door. This door says "Hello" instead of making the standard rejection sound. Note: You will not be able to take the Jammer through the door.