Maybe I'm just remembering it wrong, but this could very well be one of the places where using the diagonal walking keys is required to avoid trouble. I remember years back when I played Sierra games for a long time without knowing you could walk diagonally, using the Page Up/Page Down keys etc. If you're playing the SCI version (=better graphics than KQ1-3), which you probably are, you can also walk using the mouse, provided that you set it up to use the mouse, which may help you here.