diff --git a/vendor/clouds3d.js b/vendor/clouds3d.js
index 1396ceb..7fb270c 100644
--- a/vendor/clouds3d.js
+++ b/vendor/clouds3d.js
@@ -3620,9 +3620,14 @@ function selectEmergencyRoutes() {
         if (used[usedKey]) continue;
         used[usedKey] = true;
         var route = emergencyChainAt(cand.net, cand.ci);
-        if (cand.reverse) route.reverse();
-        var base = route.length ? route[0].d : 0;
-        for (var rp = 0; rp < route.length; rp++) route[rp].d -= base;
+        if (cand.reverse) {
+            route.reverse();
+            var maxD = route.length ? route[0].d : 0;
+            for (var rp = 0; rp < route.length; rp++) route[rp].d = maxD - route[rp].d;
+        } else if (route.length) {
+            var base = route[0].d;
+            for (var rp2 = 0; rp2 < route.length; rp2++) route[rp2].d -= base;
+        }
         var len = route.length ? route[route.length - 1].d : 0;
         if (len <= 0) {
             routeFailures.push({