Syrians are notoriously two-faced, they appear to be our friend at one time, while behind our backs assisting terrorists.
We're used to that.
they do not like terrorism in their own country, and have their own problems with fundamentalist movements. My experience with foreign embassies implies that the syrian troops around foreign embassies wouldn't play around with suspicious behavior, and might very well foil a carbomb or other type plot (is there any us embassy left in the world that is vulnerable to a car bomb? most of these places are more secure than caernarfon).
we are talking grunts, after all. they shoot things. that is their job.
all this is speculation on the 3 or 4 sentences of 'news' so far, so time will tell.