Is the principle of the sanctity of an embassy more important than the lives of human beings?

Yesterday in Ottawa, where I live, there was a riot in front of the Congolese embassy, with angry Congolese ex-patriates trying to fight their way in, breaking windows, throwing paint, and clashing with riot police. This got me thinking about a subject I’ve pondered in the past, and I went down to chat with the demonstrators, police, and reporters, to see what their opinions were regarding the question I’m about to pose to you. Out of all the people I asked, only one was able to come down on one side or the other, and even he qualified his answer when he gave it.

Embassies exist in order to facilitate communication between nations. Because matters as momentous as war and peace ride on these communications, embassies are (in theory) regarded as sacrosanct. Yet there is a long history of violation of this sanctity. For example, we now know that the Soviets used prostitutes to lure the Marine Corps guards away from their posts at the US Embassy in Moscow so that the building could be throroughly bugged. Likewise, when a sniper in the Iranian embassy on London began shooting at police, the UK police invaded the embassy and violated its sanctity to get him.

Given that the stakes can involve the destruction of the entire human race by global thermonuclear holocaust, my question is, do you believe the stakes are so high that the principle of diplomatic immunity and the sanctity of embassies is more important than the lives and safety of a smaller number of actual human beings? For example, should the British police simply have endured the snipings and erected a wall in front of the embassy? Should the police here have used deadly force to protect the (unoccupied) Congolese embassy here rather than allow it to be damaged by demonstrators?