How did the captain abandon ship so quickly?

Your question lacks enough context for a specific answer — it's unclear which captain or incident you're referring to. If you mean the Costa Concordia disaster in 2012, Captain Francesco Schettino became infamous for leaving the ship before all passengers were evacuated. He claimed he fell into a lifeboat accidentally, but investigators and the coast guard, who famously ordered him to "get back on board," found this unconvincing. He was later convicted of multiple manslaughter and abandoning ship. If you're referring to a different event, please provide more details and I can give you a more precise answer.