diff --git a/tools/render/render-core.spec.ts b/tools/render/render-core.spec.ts
index 094b9ab8..39402093 100644
--- a/tools/render/render-core.spec.ts
+++ b/tools/render/render-core.spec.ts
@@ -140,6 +140,28 @@ describe("the release's files", () => {
     }
   });
 
+  it('a request answered after its render has ended is said, never thrown', async () => {
+    // Playwright runs a route's handler itself: a rejection from it is unhandled and ends
+    // the service, as a render that timed out while its file was being read once did.
+    const root = await mkdtemp(path.join(tmpdir(), 'render-core-files-'));
+    try {
+      await mkdir(path.join(root, '98', 'diagram'), { recursive: true });
+      await writeFile(path.join(root, '98', 'diagram', 'R-HSA-1.json'), '{"x":1}');
+      const { page, seen } = routed();
+      await render(stand(page), { base: 'http://site', pathway: 'R-HSA-1', files: root }).catch(
+        () => undefined
+      );
+      const [only] = seen();
+      const handled = {
+        request: () => ({ url: () => 'https://download.reactome.org/98/diagram/R-HSA-1.json' }),
+        fulfill: () => Promise.reject(new Error('route.fulfill: Route is already handled!')),
+      } as unknown as Route;
+      await expect(only?.handler(handled)).resolves.toBeUndefined();
+    } finally {
+      await rm(root, { recursive: true, force: true });
+    }
+  });
+
   it('are left to the download site when no folder is given', async () => {
     const { page, seen } = routed();
     await render(stand(page), { base: 'http://site', pathway: 'R-HSA-1' }).catch(() => undefined);
diff --git a/tools/render/render-core.ts b/tools/render/render-core.ts
index 64f1da38..1e8836be 100644
--- a/tools/render/render-core.ts
+++ b/tools/render/render-core.ts
@@ -186,9 +186,17 @@ export async function render(
   };
   page.on('pageerror', onPageError);
   page.on('console', onConsole);
+  // A route handler's failure is no promise anyone awaits: Playwright runs the handler
+  // itself, so a rejection here is unhandled and ends the whole service. A request still
+  // being answered when the render has ended (timed out, its page closed) is "already
+  // handled" when its file arrives; that is said among the render's problems, never thrown.
   const fromFiles = async (route: Route, root: string) => {
-    const { status, contentType, body } = await localAnswer(root, new URL(route.request().url()));
-    return route.fulfill({ status, contentType, body });
+    try {
+      const { status, contentType, body } = await localAnswer(root, new URL(route.request().url()));
+      await route.fulfill({ status, contentType, body });
+    } catch (e) {
+      problems.push(`files: ${String(e).slice(0, 200)}`);
+    }
   };
   const handler = files ? (route: Route) => fromFiles(route, files) : undefined;
   if (handler) await page.route(isDownload, handler);