Whoahhhhhh!! Nothing like a Gestapo-Wannabe security guard to liven up the day eh mate!! Yeah I've had my share of unintended run-ins with these head cases. They are everywhere. In fact, I've had a very similiar situation to yours mate, where I had my head blown off verbally for taking the directions of another guard.
*The tale begins*
I arrive at the said location, front gate with single guard. I tell guard I'm going to see XXX, as you do, he opens gate and lets me in. I walk across courtyard, into foyer, and start down corridor. Two steps into corridor, the subtle hum of the air conditioner is smashed by some bloke behind me screaming "HEY!! WHERE THE HELL ARE YOU GOING AND WHO ARE YOU!!". After trying to calmly explain who I was and what I was doing, (with continued frenzied interruptions), he didn't believe me and gave me a serve. He *almost* threatened me, which would have been a huge mistake on his behalf, legally speaking. Anyhow, I somehow kept myself together, asked this second idiot to contact the first one who gave me the directions, and after this I got the second to contact the guy I was going to see (a senior and powerful member of the company). He came to the foyer as they STILL wouldn't let me through, and only then did I decide to let the volcano erupt... hehehe... aaah how very satisfying that was!
He said to me as I was on my way out after the meeting that he would have "strong words and possible actions taken" with this psycho guard. On my next visit, he informed me that that particular guard had done this several other times, and after my incident, he had been given the shaft, very hard and very dry. A fair and just ending to my tale! :D :D :D
Hope that little tale brightens things up a bit Gaz!