diff --git a/relay/test/harness.ts b/relay/test/harness.ts
index 97c7258..1ea76da 100644
--- a/relay/test/harness.ts
+++ b/relay/test/harness.ts
@@ -107,6 +107,23 @@ export async function idleTimeout(hub: DurableObjectStub, ms: number): Promise<v
   })
 }
 
+/**
+ * Bind one hub's pairing deadline, for the tests that are about the 504.
+ *
+ * Same shape and same rule as the two above. The pairing deadline was the
+ * last one still bound short for the whole pool — 250 ms, on the bet that a
+ * test's daemon always answers a round trip faster than that — and a loaded
+ * CI runner eventually collected on the bet: four pair tests 504ed at once
+ * while the runner stalled. Now the pool binds a deadline no test can
+ * outlive, and the one test about the timeout binds its own short one here.
+ */
+export async function pairTimeout(hub: DurableObjectStub, ms: number): Promise<void> {
+  await runInDurableObject(hub, (instance) => {
+    const withEnv = instance as unknown as { env: Record<string, unknown> }
+    withEnv.env = { ...withEnv.env, PAIR_TIMEOUT_MS: ms }
+  })
+}
+
 export function sleep(ms: number): Promise<void> {
   return new Promise((resolve) => setTimeout(resolve, ms))
 }
diff --git a/relay/test/pair.test.ts b/relay/test/pair.test.ts
index 2abfe6c..6b64a52 100644
--- a/relay/test/pair.test.ts
+++ b/relay/test/pair.test.ts
@@ -10,10 +10,11 @@ import {
   freshHub,
   hubPath,
   MACHINE,
+  pairTimeout,
   type Leg,
 } from './harness'
 
-/** Mirrors the PAIR_TIMEOUT_MS binding in vitest.config.ts. */
+/** The deadline the one timeout test binds for itself via pairTimeout(). */
 const PAIR_TIMEOUT_MS = 250
 
 /** The body cap, matching the daemon's own maxPairBytes (internal/daemon/pairing.go). */
@@ -292,6 +293,7 @@ describe('the cap on concurrent pairing attempts', () => {
 describe('a daemon that does not answer', () => {
   it('times out with 504 daemon did not answer', async () => {
     const hub = freshHub()
+    await pairTimeout(hub, PAIR_TIMEOUT_MS)
     const daemon = await dial(hub, `/daemon/${MACHINE}`)
     const started = Date.now()
     const res = await post(hub, '{"token":"t"}')
diff --git a/relay/vitest.config.ts b/relay/vitest.config.ts
index 946d8af..0fa5f68 100644
--- a/relay/vitest.config.ts
+++ b/relay/vitest.config.ts
@@ -23,9 +23,13 @@ import { defineConfig } from 'vitest/config'
  * before they dial. A test that says nothing about the deadline is no longer
  * making a silent bet on how fast the runner is.
  *
- * The pairing deadline stays short and stays the looser of the two, because the
- * tests that must *not* hit it run a whole HTTP request through a WebSocket
- * round trip first.
+ * The pairing deadline is bound long by the same rule, and it earned its
+ * place the same way the handshake deadline did. It used to stay short —
+ * 250 ms, on the reasoning that the tests that must not hit it run a whole
+ * HTTP request through a WebSocket round trip first — and a loaded CI
+ * runner eventually stalled past that: four pair tests 504ed in one run,
+ * none reproducible locally. The one test about the timeout binds its own
+ * short deadline with `pairTimeout()` before it dials.
  *
  * CLIENT_IDLE_TIMEOUT_MS is bound the same way and for the same reason: a test
  * client sends when its test needs it to and is otherwise silent — it sends no
@@ -41,7 +45,7 @@ export default defineConfig({
         bindings: {
           HANDSHAKE_TIMEOUT_MS: 600_000,
           CLIENT_IDLE_TIMEOUT_MS: 600_000,
-          PAIR_TIMEOUT_MS: 250,
+          PAIR_TIMEOUT_MS: 600_000,
           // The directory's entry cap, bound small for the same reason the
           // deadlines above are bound at all: the only way to test a cap is to
           // reach it, and reaching the production 512 is 512 sequential round