diff --git a/lib/base/array.cpp b/lib/base/array.cpp
index 73adcb279..fe95f5d88 100644
--- a/lib/base/array.cpp
+++ b/lib/base/array.cpp
@@ -96,7 +96,7 @@ void Array::Add(Value value)
  */
 Array::Iterator Array::Begin()
 {
-	ASSERT(OwnsLock());
+	ASSERT(Frozen() || OwnsLock());
 
 	return m_Data.begin();
 }
@@ -110,7 +110,7 @@ Array::Iterator Array::Begin()
  */
 Array::Iterator Array::End()
 {
-	ASSERT(OwnsLock());
+	ASSERT(Frozen() || OwnsLock());
 
 	return m_Data.end();
 }
@@ -327,7 +327,12 @@ Array::Ptr Array::Unique() const
 void Array::Freeze()
 {
 	ObjectLock olock(this);
-	m_Frozen = true;
+	m_Frozen.store(true, std::memory_order_release);
+}
+
+bool Array::Frozen() const
+{
+	return m_Frozen.load(std::memory_order_acquire);
 }
 
 Value Array::GetFieldByName(const String& field, bool sandboxed, const DebugInfo& debugInfo) const
diff --git a/lib/base/array.hpp b/lib/base/array.hpp
index 9589d1901..fb8257c17 100644
--- a/lib/base/array.hpp
+++ b/lib/base/array.hpp
@@ -4,6 +4,7 @@
 #define ARRAY_H
 
 #include "base/i2-base.hpp"
+#include "base/atomic.hpp"
 #include "base/objectlock.hpp"
 #include "base/value.hpp"
 #include <boost/range/iterator.hpp>
@@ -98,13 +99,14 @@ public:
 
 	Array::Ptr Unique() const;
 	void Freeze();
+	bool Frozen() const;
 
 	Value GetFieldByName(const String& field, bool sandboxed, const DebugInfo& debugInfo) const override;
 	void SetFieldByName(const String& field, const Value& value, const DebugInfo& debugInfo) override;
 
 private:
 	std::vector<Value> m_Data; /**< The data for the array. */
-	bool m_Frozen{false};
+	Atomic<bool> m_Frozen{false};
 };
 
 Array::Iterator begin(const Array::Ptr& x);
diff --git a/lib/base/dictionary.cpp b/lib/base/dictionary.cpp
index 89b6c4cbc..c45bee3d8 100644
--- a/lib/base/dictionary.cpp
+++ b/lib/base/dictionary.cpp
@@ -132,7 +132,7 @@ bool Dictionary::Contains(const String& key) const
  */
 Dictionary::Iterator Dictionary::Begin()
 {
-	ASSERT(OwnsLock());
+	ASSERT(Frozen() || OwnsLock());
 
 	return m_Data.begin();
 }
@@ -146,7 +146,7 @@ Dictionary::Iterator Dictionary::Begin()
  */
 Dictionary::Iterator Dictionary::End()
 {
-	ASSERT(OwnsLock());
+	ASSERT(Frozen() || OwnsLock());
 
 	return m_Data.end();
 }
@@ -276,7 +276,12 @@ String Dictionary::ToString() const
 void Dictionary::Freeze()
 {
 	ObjectLock olock(this);
-	m_Frozen = true;
+	m_Frozen.store(true, std::memory_order_release);
+}
+
+bool Dictionary::Frozen() const
+{
+	return m_Frozen.load(std::memory_order_acquire);
 }
 
 Value Dictionary::GetFieldByName(const String& field, bool, const DebugInfo& debugInfo) const
diff --git a/lib/base/dictionary.hpp b/lib/base/dictionary.hpp
index ba2fbe82c..f95bcc699 100644
--- a/lib/base/dictionary.hpp
+++ b/lib/base/dictionary.hpp
@@ -4,6 +4,7 @@
 #define DICTIONARY_H
 
 #include "base/i2-base.hpp"
+#include "base/atomic.hpp"
 #include "base/object.hpp"
 #include "base/value.hpp"
 #include <boost/range/iterator.hpp>
@@ -69,6 +70,7 @@ public:
 	String ToString() const override;
 
 	void Freeze();
+	bool Frozen() const;
 
 	Value GetFieldByName(const String& field, bool sandboxed, const DebugInfo& debugInfo) const override;
 	void SetFieldByName(const String& field, const Value& value, const DebugInfo& debugInfo) override;
@@ -78,7 +80,7 @@ public:
 private:
 	std::map<String, Value> m_Data; /**< The data for the dictionary. */
 	mutable std::shared_timed_mutex m_DataMutex;
-	bool m_Frozen{false};
+	Atomic<bool> m_Frozen{false};
 };
 
 Dictionary::Iterator begin(const Dictionary::Ptr& x);
diff --git a/lib/base/namespace.cpp b/lib/base/namespace.cpp
index 1f53efc92..85ed7fa1d 100644
--- a/lib/base/namespace.cpp
+++ b/lib/base/namespace.cpp
@@ -119,7 +119,12 @@ void Namespace::Remove(const String& field)
 void Namespace::Freeze() {
 	ObjectLock olock(this);
 
-	m_Frozen = true;
+	m_Frozen.store(true, std::memory_order_release);
+}
+
+bool Namespace::Frozen() const
+{
+	return m_Frozen.load(std::memory_order_acquire);
 }
 
 std::shared_lock<std::shared_timed_mutex> Namespace::ReadLockUnlessFrozen() const
@@ -160,14 +165,14 @@ bool Namespace::GetOwnField(const String& field, Value *result) const
 
 Namespace::Iterator Namespace::Begin()
 {
-	ASSERT(OwnsLock());
+	ASSERT(Frozen() || OwnsLock());
 
 	return m_Data.begin();
 }
 
 Namespace::Iterator Namespace::End()
 {
-	ASSERT(OwnsLock());
+	ASSERT(Frozen() || OwnsLock());
 
 	return m_Data.end();
 }
diff --git a/lib/base/namespace.hpp b/lib/base/namespace.hpp
index 1a028e2c5..c7f1a7e0a 100644
--- a/lib/base/namespace.hpp
+++ b/lib/base/namespace.hpp
@@ -73,6 +73,7 @@ public:
 	bool Contains(const String& field) const;
 	void Remove(const String& field);
 	void Freeze();
+	bool Frozen() const;
 
 	Iterator Begin();
 	Iterator End();