The landing had nothing to do with this, the aircraft just skidded off as it was turning off the rwy onto taxiway N.
This happened after a loooong day for the crew, KEF-AYT-EDI-KEF.
There was a layer of ice that formed VERY quickly and later that night it snowed heavily having a breaking co-efficient 0.20 which caused the 2 757's to divert to EGS.
P.S. about an hour earlier to this incident, John Travolta landed at KEF on his B707, N707JT for a fuel stop
