I'd consider the circumstances surrounding "the incident". Have there been any changes in Stryder's life that could have him feeling a bit off-balance? Schedule change, new pet or baby in the house, construction or workmen in the home, etc.? Any of these things can make him feel insecure and lead to a marking incident. If you've had another dog over for a visit, that can also prompt marking.
If it seems that he did this in response to some kind of change in his world, you'll just know you need to keep a close eye on him at times of stress. I'd try to minimize any change or stress and keep an eye on him for a few days to keep this from happening again and becoming habitual. For now, I wouldn't do much beyond that... a one-time incident may just be a fluke, so it's not time to worry yet!
Another thing to consider is whether it was a little squirt or a full pee... if it was a full pee, it may not have been marking at all. He may have had a bit too much water and/or been off his schedule and it may just have been one of those "when you've gotta go, you've gotta go!" things.
Supervise him for a few days and don't worry about this unless it happens again.
Hope this helps!
