In the level select menu, enter a code for one of the weapons that you would not normally have access to in the Embassy Missions (I.e. 7.65 Silenced). Then start the KGB HQ level. When you start the level, draw your cheat weapon and kill one of the guards. The alarm will sound, but the guards will not attack you, because the game does not recognize your weapon as one of the weapons from that level. Now that you have done this, you can beat up or shoot the guards in this level without being captured or even yelled at for. This works as both the Ambassador Aide and the Security Head chief. (Exceptions to this glitch are: Guard in front of SHc office, SHc, Guard in front of closet in Impossible difficulty. Injure them and the Guards will attack as usual.)