I knew the guy was turning, was watching him and his trailer the entire time, and was prepared to back up more than the bit that I already had if he had come any closer. I was fairly sure that he wasn't going to hit me, judging by his turning radius, and by the fact that if he was going to do so, he was going to take out a light pole and a cement wall with me.
Admittedly, I've made worse choices while biking. I didn't feel like I was in danger.
On second thought, maybe I shouldn't have been doing this: