Disclaimer: I have no legal rights to 'The Vampire Slayer' series, as it is the recognizable brain-childe of Joss Whedon. I have no legal rights to the 'Gate-verse, which is the property of Emmerich, Devlin, MGM and Carolco.
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Walter knows things. He knows exactly how many rounds for the P90 are stored in the twice-removed back-up Amory on level 26 (5498x560). He knows how many pounds of Java beans are 'stashed' for emergencies (89). He knows approximately how many times General Hammond will use his red phone this month (2). He knows how many people have higher security than him (none) and this, he knows as well, was reason he had been woken from a sound sleep and called into the debriefing room at 2148 hours.
Walter knows things. Things that tempered his reaction to learning about the program, back when Major General West knocked about the halls. Things that made the discovery of alien life on other worlds seem, while not child's play, far more likely than any man who outgrew comics should like to believe. It had been such knowledge that had pushed him into the military's path, and an unusual friendship with his not quite 'wing-man', that saw him through the Gulf War. It was the very same knowing that had him accept a position in a military he had no desire to ever be placed in again. He had been a survivor, and he had (while maybe not been entitled Champion before his acceptance into the Air Force, he still managed to have) been a fighter. A Warrior for meddlesome Powers That Be.
Walter knows things. Things he had learned when he threw-in with the good guys to save the world before. Before he had a career in the military, back when he lived on a Hellmouth. It was the reason he had been recommended for the Stargate program at the beginning. His power and command came not from successful leadership on the battlefield (though others could see these qualities if they looked beyond his loyalty in following), but the ability to adapt and acquire knowledge that smooth a path littered with sharp debris.
Yes, Walter knew things. Which is why when General Hammond passed out folders that once hidden behind so much red-tape and rubber stamped with 'classified', he merely read the mission reports. A spectacular account of failure in epic proportions. It hadn't been the first Frankenstein's Monster to be created by a government body, not by a long shot, but it had been the first near a repository of pure clogging evil. When the nine others in the once silent conference room took it upon themselves to protest the validity of the written, Walter calmly continued until the last few pages. An accounted of the last four years of clean-up, careful observations, and tentative interaction. He waited for the reason, the driving act behind the sharing of such information, the 'why' behind this meeting. He didn't have to wait long.
Walter didn't know the redheaded woman who seemed to appear in a corner's shadow several moments later. He didn't know the Rosenbergs and he certainly didn't know any Willows, but Walter did know the supernatural when he came face to face with it. Knew from her body language that she was assessing them in the manner of a Champion, a Warrior, a Protector, a Watcher, as something more than she seemed and the likes of which he only had a passing familiarity with.
Most of all, Walter knew they had one more powerful ally in a war that had no true beginning or end. It was the look in her eyes that said it all though. With everything that he had done, every little scrap of experience he had collected in a bid for life-despite-evil, she had just that little bit more. For everything Walter knew, this woman extending the white flag of friendship Knew with the incontestable way touched by mysticism.
He could see how seeped she was in the Powers, in the realities of worlds-within-worlds hidden from view. He could see that she was a kindred child Hellmouth-raised. Could see she lived under its rule far longer than he had, far longer than many were able.
As she sat at their table and began the tale, one so deeply entrenched with legend and religion and fantasy and history men the world-over were unprepared to accept, Walter watched. And if the tension slowly melted away and he looked relieved of a burden, of a weight he dutifully shouldered with an acceptance learned throughout the years, nobody made mention of it.
It was possible that nobody knew, after all, beyond the two of them.