Based on the various reports available (Times, BBC, Daily Mail, H&H etc), it does strike me as an accident
Thinking the same here, too. If he had been on the hunt and the incident had occurred there I would have suspected either malice aforethought or a poorly executed intimidation. But when it happens on the taxiway of an airport... What on earth was a hunter doing walking on a taxiway, and one frequented by his nemesis? Nobody should be on the taxiway without an aircraft around them. Sounds very dangerous.