Type ineedhelp at the Annex room with the two doors. An option menu with the following choices will appear.

Invincible player
Set to "yes" to allow the currently controlled terminator to be invincible.

Invincible terminators
Set to "yes" to allow all terminators to be invincible.

Easy close assault
Note that the terminators still may be killed even if this is set at "yes".

Player always wins
Set to "yes to allow the current mission to be completed successfully, even if all objectives are not met or the squad is killed.

No new stealers
Set to "yes" to prevent the genestealer generators from producing reinforcements.

Infinite freeze time
Unlimited time for strategy mode.

Infinite ammo
Unlimited ammunition for all weapons.

No jams or malfunctions
Prevent bolters from jamming and flamer throwers from exploding.

Allow any campaign mission to be played. Games played from this option cannot be saved.