Victory? Or just another mess?

My son hates having his diaper changed.  He fusses and struggles a lot, and that's when he's in a good mood.  I'm to the point where I would potty train him this week, if we weren't trying to sell the house.  It just doesn't seem like a good idea while selling, since my intended tactic is to keep him wearing nothing but thin underwear for a week--and I don't think those particular odors would encourage others to buy my house.  I also don't want to deal with regression after we uproot my son, so I'll be exercising patience and waiting a bit longer.  (What I'll do if this process drags on for months is still undetermined.)

However, I have been casually introducing the potty seat by placing my son on it after removing (and cleaning, if necessary) his dirty diaper, before putting on a fresh one.  I've been doing this for months now, and the idea was for him to go "accidentally" a few times in hopes that he might have an "aha!" moment.  After all, he peed on the wall regularly enough during diaper changes back when we still used the changing table, so I figured we ought to catch him a few times.

Well, today marks only the second time that he's peed between diapers since I started doing this (darn kids never do what you want them to, do they?) and you'll note I didn't say it's the second time he peed in his toilet.  He's done that once, but not today.  After setting him on this toilet today, I left the bathroom to close his drapes and get his room ready for his nap, and I can't for the life of me figure out how he was sitting or where he was aimed when he peed.  There seems to have been no pattern to where the mess went--only a drop actually went into his toilet--and the rest seems to be all over, but not in a recognizable spray pattern.  Some was under the seat where his butt should've been, some dribbled down the front, and a lot was under the toilet entirely.  It also managed to get into the bathroom rug, which is now taking its upteenth trip through the washing machine.  (I don't think I ever laundered a bath mat before having my son--vacuumed, sure, shaken out or beaten, quite frequently, but WASHED?  Nope, that's a kid thing, for me at least.)  And, of course, this happened about 2 1/2 hours before somebody's supposed to come view our house.  His timing is impeccable.  At least we have three bathrooms, so I stole the rug from the (less important) downstairs bathroom, and will let the rug dry out on the deck rather than over the edge of the tub.

So should I be happy that he, at least, peed sort of in on the toilet, and see this as progress?  Or just sigh and deal with another toddler mess?