Claiming, exactly once
Why two people clicking at the same moment cannot both read a one-view secret.
One statement
A claim is a single conditional UPDATE that decrements the view counter and returns the payload in the same statement. There is no read-then-write, so there is no window between them.
What the loser sees
The secret is gone. That is the true answer: the view was consumed by somebody else, and the ciphertext no longer exists.