Just curious Flanker, did you have a second radio that was tuned to the area frequency? If he was Medevac he would have reported it to ATC on contact with them. If I report Medevac to ATC on the area, I'll generally also report it in my CTAF taxi call as well, so that anyone who's not listening to the area frequency know's I'm in a bit of a hurry.
Sounds like there was possibly just some confusion about who's using what runway. Heck I've done it (can't say I've come head to head with anyone, but I've certainly backtracked a runway only to realise I reported backtracking 180 degree's the other way!).
Is it a runway incursion though? Not really, I don't think so. Perhaps if you were on final you could report it as being one.
morno