Nobody gets to choose "when to open the game." After sell-out, the first address to trigger the launch locks the raised ETH into the Uniswap LP in one shot; secondary trading opens and the Round #1 countdown starts in the same transaction.
Triggering the launch collects no protocol fee; you only cover the on-chain transaction fee. There is no 24-hour fallback — none is needed. Every presale buyer holds REBEL with zero secondary-market liquidity until launch, so the "I want to cash out" incentive alone drives someone to trigger. No admin safety net required.