Similar situation, different outcome: our flight from SEA arrived SIN late with only 35 min left until departure of our connecting BKK flight. Shortly before landing received SMS that we were rebooked to a BKK flight tomorrow, contact help desk for vouchers. Upon landing we ran to the gate of the departing BKK flight in T2 and made it before the door was closed (on time). The gate agent rebooked us back to the original flight as long as we were fine with our bags arriving tomorrow, which were delivered in the afternoon.