The look on Miller's face is someone that just went full lactic after giving it his all plus some on that 2 minute shift to end the game. For those of you that have never really experienced that, it causes you to get tunnel vision, confusion and you feel the need to get as much space around you as possible.
I remember finishing a 5k road race in a personal best and when my wife and 2 year old son came up to me right after the race I pushed them away momentarily to recover.
Miller was absolutely gassed and did everything he could for his team. Watch that shift again and he had to work harder than everyone else due to how the play developed.