I think a lot of players are too ready to kick when they're in the clear these days.
A lot of the time they've only got the fullback to beat, or have players in support with an overlap.
He probably wanted to fly under the radar at training and hope no one realised his condition. Turning up in an uber would have been unusual and would probably have drawn some attention.
Not saying that makes it any more excusable but just trying to work out his rationale at the time.