This looks like the old familiar 1-of-2 output. Alice creates an output that both she and Bob can spend once she shares its blinding key with Bob. Which fails when that output gets spent, but both Alice and Bob deny spending it, claiming the other party must have spent it. With 1-of-2 outputs, there’s no way to determine who spent it…
No simultaneity required. Just 2 messages, one in each direction.
Actually, it’s r·G + v·H.
Btw, Grin has a graph obfuscation protocol [1].
Grin has no maximum-time locks.