Teacher's Pet - SILVER
Before reading other's responses: This one seems fairly straightforward. I did double-check in the IPG, but my immediate conclusion is that the appropriate ruling is GPE-DEC. The nuance to the situation is that the incorrectly drawn card was drawn into an empty hand. It's in a spot where it's uniquely identifiable— I can turn to the opponent, ask “can you, with absolute certainty, point to the incorrectly drawn card” and get a yes. In such a case, the normal penalty of Game Loss should be downgraded to a warning. I'll return the card to the library, ask both players if any effects have placed known cards anywhere in the library (unlikely, given that in theory our AP just shuffled), then give it a good shuffle and present it to the opponent.
Now reading other replies, aaaaand… oooh. derp. we're resolving a tutor here. don't shuffle the tutored card back into the library. Brain fart, but I'm glad said fart occurred here, instead of at the table.
And yeah, confirm that the life was lost, ask the players to play more carefully, and move along.