diff --git a/handlers/delete_instance.go b/handlers/delete_instance.go
index 8731b68..0e195df 100644
--- a/handlers/delete_instance.go
+++ b/handlers/delete_instance.go
@@ -13,6 +13,8 @@ func DeleteInstance(rw http.ResponseWriter, req *http.Request) {
 	instanceName := vars["instanceName"]
 
 	s := services.GetSession(sessionId)
+	s.Lock()
+	defer s.Unlock()
 	i := services.GetInstance(s, instanceName)
 	err := services.DeleteInstance(s, i)
 	if err != nil {
diff --git a/handlers/new_instance.go b/handlers/new_instance.go
index be44521..8e299da 100644
--- a/handlers/new_instance.go
+++ b/handlers/new_instance.go
@@ -16,14 +16,13 @@ func NewInstance(rw http.ResponseWriter, req *http.Request) {
 	s := services.GetSession(sessionId)
 
 	s.Lock()
+	defer s.Unlock()
 	if len(s.Instances) >= 5 {
-		s.Unlock()
 		rw.WriteHeader(http.StatusConflict)
 		return
 	}
 
 	i, err := services.NewInstance(s)
-	s.Unlock()
 	if err != nil {
 		log.Println(err)
 		//TODO: Set a status error
diff --git a/services/session.go b/services/session.go
index 881616c..f4cfc33 100644
--- a/services/session.go
+++ b/services/session.go
@@ -59,8 +59,10 @@ func NewSession() (*Session, error) {
 	sessions[s.Id] = s
 
 	// Schedule cleanup of the session
-	time.AfterFunc(4*time.Hour, func() {
+	time.AfterFunc(15*time.Second, func() {
 		s = GetSession(s.Id)
+		s.Lock()
+		defer s.Unlock()
 		wsServer.BroadcastTo(s.Id, "session end")
 		log.Printf("Starting clean up of session [%s]\n", s.Id)
 		for _, i := range s.Instances {