That Sisselak joke - it´s a very bad pun, and they´re laughing at how bad it is. Not at the joke itself

Robert Gustafsson, Johan Rheborg and Henrik Schyffert were all part of “Killinggänget”. A group of six comedians formed beginning of 90ies, that had their break at mid(90ies) with “NileCity 105,6” also “I manegen med Glen Killing” and after that a lot more. Hard to follow if you haven’t experienced the references I guess. Some of it is probably on KZfaq subs not so much perhaps

One of the jokes he tells abouth Henrik is basicly "he knows nothing" - and it is a reference to a stand up rutine Henrik did some years earlier where he stated that he actually know nothing but somehow things worked out for him - he was in a band (Whale), he became a famous comedian (with Robert and Johan and others), and he became the boss over a TV channels that was aimed mostly towards teens and young adaults - all this without knowing ANYTHING (according to himself)

3:42 They are laughing at the punny title of Sissela's DVD. Except for too long.

Elak means mean.