Thats because the guy who shot it wasnt flying the plane as well, he only had to focus on shooting the target, let alone kepping the plane flying. And the Lancaster was designed to fly at night and I take it the gunners were trained to shoot in the dark too.
A guy going up in a dayfighter with no radar or matt black paint or whatever those things are that are put on the guns to stop the flash blinding the pilot, and taking out 2 planes that did have that equipment is damn good...
And the P-38 was a fighter lanc...