diff --git a/tests/e2e/lifecycle.py b/tests/e2e/lifecycle.py
index ecbfee2c579..fdf2137584e 100644
--- a/tests/e2e/lifecycle.py
+++ b/tests/e2e/lifecycle.py
@@ -22,7 +22,8 @@ class E2ECase(Protocol):
     """A stateful e2e check run against a long-lived proxy.
 
     init() acquires resources, run() exercises behaviour and asserts, teardown()
-    releases everything init() created. teardown() must run even if run() raises.
+    releases everything init() created. teardown() must run even if init() fails
+    partway or run() raises.
     """
 
     def init(self) -> None: ...
@@ -35,11 +36,14 @@ class E2ECase(Protocol):
 def run_case(case: E2ECase) -> None:
     """Drive a case through its lifecycle: init -> run -> teardown.
 
-    teardown always runs, even if run() raises (or skips), so resources the case
-    created on the long-lived proxy are released.
+    teardown always runs - even when init() fails partway or run() raises (or
+    skips) - so resources the case already registered on the long-lived proxy are
+    released. init() is inside the try because cases register cleanups
+    progressively (e.g. create team, then user, then key), and a failure after
+    the first creation must still release what came before.
     """
-    case.init()
     try:
+        case.init()
         case.run()
     finally:
         case.teardown()
diff --git a/tests/e2e/test_lifecycle.py b/tests/e2e/test_lifecycle.py
new file mode 100644
index 00000000000..d3c559dd2ed
--- /dev/null
+++ b/tests/e2e/test_lifecycle.py
@@ -0,0 +1,46 @@
+"""Unit coverage for the lifecycle harness (lifecycle.run_case).
+
+Cases register cleanups progressively during init() (create team, then user, then
+key), so a failure partway through init() must still release whatever was already
+created on the long-lived shared proxy. This guards that contract.
+"""
+
+from dataclasses import dataclass, field
+from typing import Callable, List
+
+import pytest
+
+from lifecycle import run_case
+
+
+@dataclass
+class _PartialInitCase:
+    """init() registers a cleanup, then raises before finishing - mirroring a real
+    case that creates a resource, registers its delete, then fails on the next
+    step."""
+
+    released: List[str] = field(default_factory=list)
+    _undo: List[Callable[[], None]] = field(default_factory=list)
+
+    def init(self) -> None:
+        self._undo.append(lambda: self.released.append("first"))
+        raise RuntimeError("init failed after registering the first resource")
+
+    def run(self) -> None:
+        raise AssertionError("run() must not execute when init() failed")
+
+    def teardown(self) -> None:
+        for undo in reversed(self._undo):
+            undo()
+
+
+def test_run_case_releases_resources_when_init_fails_partway() -> None:
+    case = _PartialInitCase()
+
+    with pytest.raises(RuntimeError, match="init failed"):
+        run_case(case)
+
+    assert case.released == ["first"], (
+        "a resource registered before init() failed must still be released, or it "
+        "leaks on the long-lived shared proxy"
+    )