diff --git a/src/datatypes/structures.js b/src/datatypes/structures.js
index 4cb7c04..8e3b13d 100644
--- a/src/datatypes/structures.js
+++ b/src/datatypes/structures.js
@@ -97,17 +97,14 @@ function sizeOfArray(value, typeArgs, rootNode) {
 }
 
 
-function readContainer(buffer, offset, typeArgs, rootNode) {
+function readContainer(buffer, offset, typeArgs, context) {
   var results = {
-    value: {},
+    value: { "..": context },
     size: 0
   };
-  var backupThis = rootNode.this;
-  rootNode.this = results.value;
   typeArgs.forEach((typeArg) => {
-    var readResults;
     tryCatch(() => {
-      readResults = this.read(buffer, offset, typeArg.type, rootNode);
+      var readResults = this.read(buffer, offset, typeArg.type, results.value);
       results.size += readResults.size;
       offset += readResults.size;
       if (typeArg.anon) {
@@ -124,19 +121,18 @@ function readContainer(buffer, offset, typeArgs, rootNode) {
       throw e;
     });
   });
-  rootNode.this = backupThis;
+  delete results.value[".."];
   return results;
 }
 
-function writeContainer(value, buffer, offset, typeArgs, rootNode) {
-  var backupThis = rootNode.this;
-  rootNode.this = value;
+function writeContainer(value, buffer, offset, typeArgs, context) {
+  value[".."] = context;
   typeArgs.forEach((typeArg) => {
     tryCatch(() => {
       if (typeArg.anon)
-        offset = this.write(value, buffer, offset, typeArg.type, rootNode);
+        offset = this.write(value, buffer, offset, typeArg.type, value);
       else
-        offset = this.write(value[typeArg.name], buffer, offset, typeArg.type, rootNode);
+        offset = this.write(value[typeArg.name], buffer, offset, typeArg.type, value);
     }, (e) => {
       if (typeArgs && typeArg && typeArg.name)
         addErrorField(e, typeArg.name);
@@ -145,20 +141,19 @@ function writeContainer(value, buffer, offset, typeArgs, rootNode) {
       throw e;
     });
   });
-  rootNode.this = backupThis;
+  delete value[".."];
   return offset;
 }
 
-function sizeOfContainer(value, typeArgs, rootNode) {
+function sizeOfContainer(value, typeArgs, context) {
+  value[".."] = context;
   var size = 0;
-  var backupThis = rootNode.this;
-  rootNode.this = value;
   typeArgs.forEach((typeArg) => {
     tryCatch(() => {
       if (typeArg.anon)
-        size += this.sizeOf(value, typeArg.type, rootNode);
+        size += this.sizeOf(value, typeArg.type, value);
       else
-        size += this.sizeOf(value[typeArg.name], typeArg.type, rootNode);
+        size += this.sizeOf(value[typeArg.name], typeArg.type, value);
     }, (e) => {
       if (typeArgs && typeArg && typeArg.name)
         addErrorField(e, typeArg.name);
@@ -167,7 +162,7 @@ function sizeOfContainer(value, typeArgs, rootNode) {
       throw e;
     });
   });
-  rootNode.this = backupThis;
+  delete value[".."];
   return size;
 }
 
diff --git a/src/transforms/serializer.js b/src/transforms/serializer.js
index 2e8334e..0f2dd6f 100644
--- a/src/transforms/serializer.js
+++ b/src/transforms/serializer.js
@@ -63,7 +63,7 @@ var packetStates = packetIndexes.packetStates;
 function createPacketBuffer(packetName, state, params, isServer) {
   var direction = !isServer ? 'toServer' : 'toClient';
   var packetId = packetIds[state][direction][packetName];
-  assert.notEqual(packetId, undefined);
+  assert.notEqual(packetId, undefined, `${state}.${isServer}.${packetName} : ${packetId}`);
   var packet = get(packetName, state, !isServer);
   assert.notEqual(packet, null);
 
@@ -140,7 +140,8 @@ function parsePacketData(buffer, state, isServer, packetsToParse = {"packet": tr
   results.data = res.value;
   cursor += res.size;
   if(buffer.length > cursor)
-    throw new Error(`Read error for ${packetName} : Packet data not entirely read`);
+    throw new Error(`Read error for ${packetName} : Packet data not entirely read :
+        ${JSON.stringify(results)}`);
   debug(results);
   return results;
 }
diff --git a/src/utils.js b/src/utils.js
index d380577..03d2e42 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -5,13 +5,18 @@ module.exports = {
   tryCatch: tryCatch,
 };
 
-function getField(countField, rootNode) {
-  var countFieldArr = countField.split(".");
-  var count = rootNode;
-  for(var index = 0; index < countFieldArr.length; index++) {
-    count = count[countFieldArr[index]];
+function getField(countField, context) {
+  var countFieldArr = countField.split("/");
+  var i = 0;
+  if (countFieldArr[i] === "") {
+    while (context.hasOwnProperty(".."))
+      context = context[".."];
+    i++;
   }
-  return count;
+  for(; i < countFieldArr.length; i++) {
+    context = context[countFieldArr[i]];
+  }
+  return context;
 }
 
 function getFieldInfo(fieldInfo) {