diff --git a/ssh/execute.go b/ssh/execute.go
index 8565b56..6a7008b 100644
--- a/ssh/execute.go
+++ b/ssh/execute.go
@@ -8,6 +8,8 @@ import (
 )
 
 func (m *Manager) ExecuteEverywhere(cmd string) {
+	m.clientsMUX.Lock()
+	defer m.clientsMUX.Unlock()
 	for host, client := range m.clients {
 		m.execute(host, client, cmd)
 	}
diff --git a/ssh/run.go b/ssh/run.go
index 54a518e..2cdf030 100644
--- a/ssh/run.go
+++ b/ssh/run.go
@@ -24,9 +24,13 @@ func SSHResultToStringHandler(handler SSHResultHandler) SSHResultHandler {
 }
 
 func (m *Manager) RunEverywhere(cmd string, handler SSHResultHandler) {
+	m.clientsMUX.Lock()
+	defer m.clientsMUX.Unlock()
 	for host, client := range m.clients {
-		result, err := m.run(host, client, cmd)
-		handler(host, result, err)
+		go func() {
+			result, err := m.run(host, client, cmd)
+			handler(host, result, err)
+		}()
 	}
 }