Why so teams never Look at opponents time.

China cinceded after 9 ends against canada. But canada only Had 3 minutes left. thAts Only 22.5 Seconds per Stone. So Not very much. Why do Teams Not Ever Keep Their opponents time in Mind. I am coincident thAt they either could have Made canada Run Out of Time or get Them To Rush and miss one or Two rocks. They Just need To Give Them a Bit of Things To think about and ITS possible