Take off and landing from the Polderbaan within a 'small' time period is very unusual, as there is no taxiway parallel to the runway! Thus, if it is set for "36L" usage (i.e. taking off towards the north), then planes can't land (from the south) as they'd be stuck at the north end of the runway; similarly, when it's in "18R" usage (landing from the north), then planes can't get to the north end for taking off towards the south. At least, that's how I understand it - others may know better.

Maybe you took off from "18C" - the taxi to the north end of this runway is almost as long as to the south end of the Polderbaan; or, similarly, maybe you landed on "36C".

-- Henry