It's not a surprise to see Arthur here - Eames hasn't known him long, but he can tell the man has a particular soft spot for witches. Maybe it has to do with his former employer, there's a particular kind of bond- a closeness that's bred by protection. A fair guess, but Eames wouldn't claim to know for sure.

Like the annoying shadow he often is, Eames comes up beside Arthur quietly. Standing in silent observation of the bonfire before he tilts his head a little and speaks softly, "we really must stop meeting like this."