Things change. I'm sure he might've intended to play them at some point. Genuinely. Then during the game he might have decided that actually, no - he wants the players to focus. It wasn't a great first 45 imo - one paced, bit boring. So maybe he wanted the team to show something in the second half. Firmly stamp home that improved recent confidence, go for more goals, get more minutes, be ruthless. Looked to me that he felt that he had to send a message to the players that there can be no drop off as they look to find their form. You don't have to agree, but it's not without logic.