diff --git a/ci.sh b/ci.sh
index 87d63d2..27ae3af 100755
--- a/ci.sh
+++ b/ci.sh
@@ -45,25 +45,22 @@ boundaries_fire() {
 
 leg "import boundaries fire ($node_image)" boundaries_fire
 
-# Without `docker run --init`, process 1 ignores the SIGINT docker forwards and the container runs to its end.
 interrupt_stops_container() {
-  local pid ready started waited=0
+  local pid ready status=0 waited=0
   ready=$(mktemp) || return 1
   in_image "$node_image" sh -c 'echo ready; sleep 60' > "$ready" &
   pid=$!
   until grep -q ready "$ready"; do
     waited=$((waited + 1))
-    [ "$waited" -le 300 ] || return 1
+    [ "$waited" -le 300 ] || { kill -INT "$pid"; rm -f "$ready"; return 1; }
     sleep 0.2
   done
-  kill -INT "$pid"
-  started=$SECONDS
-  wait "$pid" || true
+  kill -INT "$pid" && wait "$pid" || status=$?
   rm -f "$ready"
-  [ $((SECONDS - started)) -lt 20 ]
+  [ "$status" -eq 130 ]
 }
 
-leg "Ctrl-C stops a leg's container ($node_image)" interrupt_stops_container
+leg "Ctrl-C stops an in_image container ($node_image)" interrupt_stops_container
 
 test_log=$(mktemp)
 node_tests() {
diff --git a/docker-runner.sh b/docker-runner.sh
index e76243f..98c0aa7 100644
--- a/docker-runner.sh
+++ b/docker-runner.sh
@@ -6,6 +6,7 @@ firefox_image=selenium/standalone-firefox:159.0.1
 floor_image=node:18.20.8-alpine3.21
 node_image=node:26.13.0-alpine3.24
 
+# --init: the container's process 1 ignores a SIGINT it has no handler for, so without it Ctrl-C leaves the container running.
 in_image() {
   local image=$1 entrypoint=$2
   shift 2