diff --git a/packages/runtime/src/scr_node_island.c b/packages/runtime/src/scr_node_island.c
index 1a6ce307f..c3104393f 100644
--- a/packages/runtime/src/scr_node_island.c
+++ b/packages/runtime/src/scr_node_island.c
@@ -499,13 +499,27 @@ static const ScrNodeBridgeHost ni_host = {
     &scr_ni_host_shared_tdz,
 };
 
+typedef struct {
+  uint32_t event, listener;
+  const char *name;
+  int arg;
+} NiEmit;
+
+static void ni_emit_job(void *p) {
+  NiEmit *e = p;
+  ni_bridge->emit(e->event, e->listener, e->name, e->arg);
+}
+
+/* An island listener of a process event, on Node's stack (an exit listener
+ * runs from the runtime's exit sequence, on whatever stack called it). */
 void scr_node_island_emit(uint32_t event, uint32_t listener, ScrStr *name, int arg) {
   if (ni_bridge == NULL) return;
   char *n = malloc(name->len + 1);
   if (n == NULL) ni_oom();
   memcpy(n, name->data, name->len);
   n[name->len] = '\0';
-  ni_bridge->emit(event, listener, n, arg);
+  NiEmit e = {event, listener, n, arg};
+  ni_on_node_stack(ni_emit_job, &e);
   free(n);
 }
 
@@ -548,7 +562,75 @@ static int ni_run_loop(int continue_turn) {
   return a.code;
 }
 
-/* The bridge as the hosted loop sees it: Node's loop runs on Node's stack. */
+/* The bridge as the hosted loop sees it. Every entry that runs JavaScript
+ * (scheduling a tick, timer or immediate goes through the bootstrap's
+ * helpers; a checkpoint drains queues; Node's loop) runs on Node's stack,
+ * below the mark when it comes from an async fiber that a host callback
+ * resumed, like every other entry: V8 scans only Node's stack, so no frame
+ * of Node may live on a fiber's stack or the main thread's. */
+typedef struct {
+  int op;
+  uint32_t a, b;
+  double d0, d1;
+  int i0;
+  uint32_t result;
+} NiHosted;
+
+enum {
+  NI_H_MICROTASK,
+  NI_H_TICK,
+  NI_H_TIMER,
+  NI_H_TIMER_CLEAR,
+  NI_H_TIMER_REF,
+  NI_H_TIMER_REFRESH,
+  NI_H_IMMEDIATE,
+  NI_H_IMMEDIATE_CLEAR,
+  NI_H_IMMEDIATE_REF,
+  NI_H_CHECKPOINT,
+};
+
+static void ni_hosted_job(void *p) {
+  NiHosted *h = p;
+  switch (h->op) {
+  case NI_H_MICROTASK: ni_bridge->microtask(h->a); break;
+  case NI_H_TICK: ni_bridge->tick(h->a); break;
+  case NI_H_TIMER: h->result = ni_bridge->timer(h->d0, h->d1, h->i0, h->a); break;
+  case NI_H_TIMER_CLEAR: ni_bridge->timer_clear(h->a); break;
+  case NI_H_TIMER_REF: ni_bridge->timer_ref(h->a, h->i0); break;
+  case NI_H_TIMER_REFRESH: ni_bridge->timer_refresh(h->a); break;
+  case NI_H_IMMEDIATE: h->result = ni_bridge->immediate(h->i0, h->a); break;
+  case NI_H_IMMEDIATE_CLEAR: ni_bridge->immediate_clear(h->a); break;
+  case NI_H_IMMEDIATE_REF: ni_bridge->immediate_ref(h->a, h->i0); break;
+  case NI_H_CHECKPOINT: ni_bridge->checkpoint(h->i0); break;
+  default: break;
+  }
+}
+
+static uint32_t ni_hosted_run(int op, uint32_t a, double d0, double d1, int i0) {
+  NiHosted h = {op, a, 0, d0, d1, i0, 0};
+  ni_on_node_stack(ni_hosted_job, &h);
+  return h.result;
+}
+
+static void ni_h_microtask(uint32_t token) { ni_hosted_run(NI_H_MICROTASK, token, 0, 0, 0); }
+static void ni_h_tick(uint32_t token) { ni_hosted_run(NI_H_TICK, token, 0, 0, 0); }
+static uint32_t ni_h_timer(double delay, double repeat, int ref, uint32_t token) {
+  return ni_hosted_run(NI_H_TIMER, token, delay, repeat, ref);
+}
+static void ni_h_timer_clear(uint32_t h) { ni_hosted_run(NI_H_TIMER_CLEAR, h, 0, 0, 0); }
+static void ni_h_timer_ref(uint32_t h, int ref) { ni_hosted_run(NI_H_TIMER_REF, h, 0, 0, ref); }
+static void ni_h_timer_refresh(uint32_t h) { ni_hosted_run(NI_H_TIMER_REFRESH, h, 0, 0, 0); }
+static uint32_t ni_h_immediate(int ref, uint32_t token) {
+  return ni_hosted_run(NI_H_IMMEDIATE, token, 0, 0, ref);
+}
+static void ni_h_immediate_clear(uint32_t h) { ni_hosted_run(NI_H_IMMEDIATE_CLEAR, h, 0, 0, 0); }
+static void ni_h_immediate_ref(uint32_t h, int ref) {
+  ni_hosted_run(NI_H_IMMEDIATE_REF, h, 0, 0, ref);
+}
+static void ni_h_checkpoint(int microtasks_first) {
+  ni_hosted_run(NI_H_CHECKPOINT, 0, 0, 0, microtasks_first);
+}
+
 static ScrNodeBridge ni_hosted;
 
 /* ── loading Node ─────────────────────────────────────────────────────── */
@@ -622,6 +704,16 @@ static void ni_start(void) {
   scr_atexit(ni_stop_atexit);
   ni_hosted = *bridge;
   ni_hosted.run_loop = &ni_run_loop;
+  ni_hosted.microtask = &ni_h_microtask;
+  ni_hosted.tick = &ni_h_tick;
+  ni_hosted.timer = &ni_h_timer;
+  ni_hosted.timer_clear = &ni_h_timer_clear;
+  ni_hosted.timer_ref = &ni_h_timer_ref;
+  ni_hosted.timer_refresh = &ni_h_timer_refresh;
+  ni_hosted.immediate = &ni_h_immediate;
+  ni_hosted.immediate_clear = &ni_h_immediate_clear;
+  ni_hosted.immediate_ref = &ni_h_immediate_ref;
+  ni_hosted.checkpoint = &ni_h_checkpoint;
   scr_loop_host(&ni_hosted, since);
   /* NI-7: deferred island modules evaluate now, before the operation that
    * needed Node, in their import order. */