While I agree with the arguments that an understudy should have been planned for, this was absolutely NOT a situation where you could just throw someone in last minute. It doesn't matter if they've played Roger on stage a thousand times and can do the role in their sleep. This required months of planning and rehearsal and choreography to deal with the scale of the set, the movement of the cameras, the movement of bodies, the audience, etc.
"...everyone finally shut up, and the audience could enjoy the beginning of the Anatevka Pogram in peace."