@@ -1,6 +1,7 @@
 /* eslint-disable @typescript-eslint/ban-ts-comment */
 import {
 Injectable,
+Injector,
 NgZone,
 PendingTasks,
 inject
@@ -97,7 +98,7 @@ const zoneWrapFn = (
 ) => {
 return (...args: any[]) => {
 if (taskDone) {
-setTimeout(taskDone, 10);
+setTimeout(taskDone, 0);
 }
 return run(() => it.apply(this, args));
 };
@@ -108,12 +109,22 @@ export const ɵzoneWrap = <T= unknown>(it: T, blockUntilFirst: boolean): T => {
 return function () {
 let taskDone: VoidFunction | undefined;
 const _arguments = arguments;
+let schedulers: ɵAngularFireSchedulers;
+let pendingTasks: PendingTasks;
+let injector: Injector;
+try {
+schedulers = getSchedulers();
+pendingTasks = inject(PendingTasks);
+injector = inject(Injector);
+} catch(e) {
+return (it as any).apply(this, _arguments);
+}
 // if this is a callback function, e.g, onSnapshot, we should create a pending task and complete it
 // only once one of the callback functions is tripped.
 for (let i = 0; i < arguments.length; i++) {
 if (typeof _arguments[i] === 'function') {
 if (blockUntilFirst) {
-taskDone ||= run(() => inject(PendingTasks).add());
+taskDone ||= run(() => pendingTasks.add());
 }
 // TODO create a microtask to track callback functions
 _arguments[i] = zoneWrapFn(_arguments[i], taskDone);
@@ -122,7 +133,6 @@ export const ɵzoneWrap = <T= unknown>(it: T, blockUntilFirst: boolean): T => {
 const ret = runOutsideAngular(() => (it as any).apply(this, _arguments));
 if (!blockUntilFirst) {
 if (ret instanceof Observable) {
-const schedulers = getSchedulers();
 return ret.pipe(
 subscribeOn(schedulers.outsideAngular),
 observeOn(schedulers.insideAngular),
@@ -132,18 +142,17 @@ export const ɵzoneWrap = <T= unknown>(it: T, blockUntilFirst: boolean): T => {
 }
 }
 if (ret instanceof Observable) {
-const schedulers = getSchedulers();
 return ret.pipe(
 subscribeOn(schedulers.outsideAngular),
 observeOn(schedulers.insideAngular),
-pendingUntilEvent(),
+pendingUntilEvent(injector),
 );
 } else if (ret instanceof Promise) {
 // eslint-disable-next-line @typescript-eslint/no-misused-promises
 return run(
 () =>
 new Promise((resolve, reject) => {
-inject(PendingTasks).run(() => ret).then(
+pendingTasks.run(() => ret).then(
 (it) => run(() => resolve(it)),
 (reason) => run(() => reject(reason))
 );
@@ -153,7 +162,7 @@ export const ɵzoneWrap = <T= unknown>(it: T, blockUntilFirst: boolean): T => {
 // Handle unsubscribe
 // function() is needed for the arguments object
 return function () {
-setTimeout(taskDone, 10);
+setTimeout(taskDone, 0);
 return ret.apply(this, arguments);
 };
 } else {