As a number of people have pointed out, if the hypothetical MI5 ends just before a cliffhanger, it's going to look a bit rubbsh, even to people who are familar with "Launch of the Screaming Narwhal".
*On the other hand*, it might be fun if somebody used the Telltale Tool to create a mini-movie covering all this prelude to put on the DVD. Well, either that or having a "I Wonder What Happens Before Tales of Monkey Island". Or preferably both.....