It is normally easy to get out of the way, since I am almost always on the shoulder or as close to the right side of the road as possible. I have had trouble with emergency vehicles twice, one of which still (it was in 1995) make me think how close it was.
I was on a tour with two friends when we came to a road construction. One lane (the right one) had just been given a new layer of tarmac for about three kilometres. There were traffic lights at each end of this stretch since there was only one lane left. We realized that we probably wouldn't make it through before they let on on-coming traffic, but figured we would hear them and be able to pull over. Also worth mentioning is the fact that there was a height difference (4-5 cm) between the old tarmac and the new.
There we were riding along, all cars going in our direction long gone, waiting for on-coming traffic. Suddenly an ambulance came around a corner no more than 40 metres ahead of us, doing more than 100 kph. Despite the complete silence (there were no other cars for a kilometre in either direction) we didn't hear the sirens until we saw the car. We all managed to get the bikes up on the new tarmac, but it is one of my closest calls yet.
The other time was more of a misunderstanding when touring in England in 1997. I had got out of the way, but in a somewhat exposed situation. So I delayed two police cars and one police bus for a couple of seconds. Since that incident I have tried to be clearer with my intentions in such situations, but it has happened that I haven't heard sirens almost until they pass me (and there is nothing wrong with my ears
).
/Csson