diff --git a/builder/googlecompute/step_start_tunnel.go b/builder/googlecompute/step_start_tunnel.go
index 031fb06be..7536f705c 100644
--- a/builder/googlecompute/step_start_tunnel.go
+++ b/builder/googlecompute/step_start_tunnel.go
@@ -100,7 +100,10 @@ func (s *StepStartTunnel) createTempGcloudScript(args []string) (string, error)
 	s.IAPConf.IAPHashBang = fmt.Sprintf("#!%s\n", s.IAPConf.IAPHashBang)
 	log.Printf("[INFO] (google): Prepending inline gcloud setup script with %s",
 		s.IAPConf.IAPHashBang)
-	writer.WriteString(s.IAPConf.IAPHashBang)
+	err = writer.WriteString(s.IAPConf.IAPHashBang)
+	if err != nil {
+		return "", fmt.Errorf("Error preparing inline hashbang: %s", err)
+	}
 
 	// authenticate to gcloud
 	_, err = writer.WriteString(
@@ -128,7 +131,10 @@ func (s *StepStartTunnel) createTempGcloudScript(args []string) (string, error)
 	// figure out what extension the file should have, and rename it.
 	tempScriptFileName := tf.Name()
 	if s.IAPConf.IAPExt != "" {
-		os.Rename(tempScriptFileName, fmt.Sprintf("%s%s", tempScriptFileName, s.IAPConf.IAPExt))
+		err := os.Rename(tempScriptFileName, fmt.Sprintf("%s%s", tempScriptFileName, s.IAPConf.IAPExt))
+		if err != nil {
+			return "", fmt.Errorf("Error setting the correct temp file extension: %s", err)
+		}
 		tempScriptFileName = fmt.Sprintf("%s%s", tempScriptFileName, s.IAPConf.IAPExt)
 	}
 
@@ -179,7 +185,6 @@ func (s *StepStartTunnel) Run(ctx context.Context, state multistep.StateBag) mul
 	}
 	defer os.Remove(tempScriptFileName)
 
-	// Shell out to gcloud.
 	s.tunnelDriver = NewTunnelDriver()
 
 	err = retry.Config{
@@ -201,5 +206,4 @@ func (s *StepStartTunnel) Run(ctx context.Context, state multistep.StateBag) mul
 // Cleanup stops the IAP tunnel and cleans up processes.
 func (s *StepStartTunnel) Cleanup(state multistep.StateBag) {
 	s.tunnelDriver.StopTunnel()
-	return
 }
diff --git a/builder/googlecompute/tunnel_driver.go b/builder/googlecompute/tunnel_driver.go
index b07bc2ef2..78d9be634 100644
--- a/builder/googlecompute/tunnel_driver.go
+++ b/builder/googlecompute/tunnel_driver.go
@@ -36,7 +36,6 @@ func (t *TunnelDriverLinux) StartTunnel(cancelCtx context.Context, tempScriptFil
 	if err != nil {
 		err := fmt.Errorf("Error calling gcloud sdk to launch IAP tunnel: %s",
 			err)
-		cmd.Process.Kill()
 		return err
 	}
 	// Wait for tunnel to launch and gather response. TODO: do this without
@@ -53,9 +52,8 @@ func (t *TunnelDriverLinux) StartTunnel(cancelCtx context.Context, tempScriptFil
 	serr := stderr.String()
 	log.Println(serr)
 	if strings.Contains(serr, "ERROR") {
-		cmd.Process.Kill()
 		errIdx := strings.Index(serr, "ERROR:")
-		return fmt.Errorf("ERROR: %s", serr[errIdx+7:len(serr)])
+		return fmt.Errorf("ERROR: %s", serr[errIdx+7:])
 	}
 	// Store successful command on step so we can access it to cancel it
 	// later.
@@ -72,7 +70,10 @@ func (t *TunnelDriverLinux) StopTunnel() {
 		// daemon child. We create the group ID with the syscall.SysProcAttr
 		// call inside the retry loop above, and then store that ID on the
 		// command so we can destroy it here.
-		syscall.Kill(-t.cmd.Process.Pid, syscall.SIGKILL)
+		err := syscall.Kill(-t.cmd.Process.Pid, syscall.SIGKILL)
+		if err != nil {
+			log.Printf("Issue stopping IAP tunnel: %s", err)
+		}
 	} else {
 		log.Printf("Couldn't find IAP tunnel process to kill. Continuing.")
 	}