Just saw some deleted footage.
What i havent seen yet, but have read, is that Marlon saw Truman escape, but let it happen anyway. Its on the DVD footage, ive read that here on IMDB.
What I Have SEEN however, is another deleted scene where the key actors, the wife, Marlon, new GF to be, are on a job brief, is Marlon being disgusted with the humanity of it all.
In the script, Truman has disguised himself as a homeless person and he wanders freely among the other townspeople who are looking for him. They don't recognize him, but Marlon does. There's a moment of hesitation where we're left to wonder whether or not Marlon will point Truman out to the others, but then he doesn't. He walks off at the last minute, and continues the search.
I don't believe that scene was ever actually filmed, but this one is similar.
https://www.youtube.com/watch?v=Wh7UjOAa_9Y
According to the back story actor Noah Emmerich came up with for his character, the friendship between Lois 'Marlon' Coltrane was real because they were just kids when they met, and as Marlon got older he experienced guilt which caused him to develop destructive habits (alcohol, drug addiction, etc).
What, you thought I was being serious?
i always thought Marlon secretly hinted that Truman's suspicions were correct when he says something like
"if everyone is in on it.. i HAVE to be in on it too"
i feel like his character always wished for Truman to escape
It's an interesting situation with Marlon. He genuinely seemed to like Truman and it's kind of a shame that we don't get to see his reaction at the end, when Truman walks out that door.
I've always thought it would have been so cool to whack golf balls like they did, on that little stretch of road at night. I got the feeling that was something they did from time to time... probably not every night, but every now and again.