The engine fuel pump and even the aircraft boost pumps are sized to be able to provide considerably more fuel than the engine will require. This gives them a margin so if they degrade or some restriction occurs the engine will not be starved.
Since the engine continued to operate and even pull some power in reverse it would appear this was not a total "rupture" of the fuel line but a leak,albeit ba ig one. However it is obvious that there was enough fuel being provided by the pump to sustain engine operation and keep the leak going.
Being retired I am cut off from sources of IPC and other drawings. Would love to see on illustrating what went wrong.