The problem with the call - and calls like these - is it requires you read the player's mind, and presume he must look at the ball to contest the ball. It's more common sense than that: a player can both be aware of the ball's trajectory, other players in the contest AND be concerned about his own safety. In fact, he MUST have that awareness in his peripheral vision, otherwise he'll end up on a stretcher.
This contradicts rulings of "careless" in defence, where the player has to be aware of not only his goal in stopping the offensive player, but the well-being of that player.
In my opinion, Walsh is well within his rights to avert his eyes from the ball in pursuit of it, and it's beyond the bunker to read his mind. If the referee or touch judge watched him make a beeline for another player and deliberately take him out, there was no need to involve the bunker.