Survivors claiming that U-20 surfaced directly after the sinking

Hello all

I was recently listening to audio interviews with survivors: May Bird and Alice Lines, and noticed that both of them claimed that U-20 surfaced shortly after torpedoing the Lusitania. Bird stated: "I saw the submarine come up. They were lined up on the deck. They all stood in a row. They stayed there for quite awhile, then they vanished." Lines' 1989 interview can be found on the weblink below, and she mentions U-20 approximately 18 minutes into Reel 1:

Drury Alice Maud IWM interview (10777)

However, after reading through the testimonies of survivors from the British inquiry, I noted that none of them mentioned anything about seeing the U-boat surfacing directly after the sinking, although Leslie Morton thought he saw the submarine's conning tower submerging (before the torpedo hit), Theodore Diamandis insisted he saw a periscope on the port side, and Andrew Cockburn claimed that he saw a periscope four hours after the sinking. Lines also testified at the inquiry and made no mention of seeing U-20. Furthermore, Walther Schwieger's war diary maintains that his U-boat torpedoed the liner from a depth of 11 metres, dived to 24 metres after the sinking and later came back up to 11 metres after almost an hour - but mentions nothing about surfacing his vessel. Consequently, I am wondering why Bird and Lines claimed, later in their lives, that the submarine surfaced directly after the sinking. What do you think is the most likely explanation?
I do not know much about Lusitania but after the stupid submarine, U-20 (sorry, I hate subs that torpedo everything in sight) torpedoed the Lusitania, it surfaced. When the people in the sub saw all the panic and tragedy on the Lusitania, they felt really bad about it and I think just went away.