In a secret room in Singapore hangar below control switch you'll find level 5 computer and cooling upgrade. There is an email on a computer named 'Hangar 18,' written by Dave One. This contains sections of the lyrics to the Megadeth song Hanger One. The computer user MSTAINE is a reference to Megadeth member Dave Mustaine.

Note that finding this computer grants the Hangar 18 Trophy / Achievement.