diff --git a/apps/plugins/doom/p_floor.c b/apps/plugins/doom/p_floor.c
index bbcf2bc358..f4dbcd04f5 100644
--- a/apps/plugins/doom/p_floor.c
+++ b/apps/plugins/doom/p_floor.c
@@ -911,7 +911,7 @@ int EV_DoDonut(line_t*  line)
          // killough 4/5/98: changed demo_compatibility to compatibility
          if (comp[comp_model])
          {
-            if ((!s2->lines[i]->flags & ML_TWOSIDED) ||
+            if (!(s2->lines[i]->flags & ML_TWOSIDED) ||
                   (s2->lines[i]->backsector == s1))
                continue;
          }