Arc burn hit them back. And if you think a Titan bubble will help it won't the psion blast will tear through that as well. Edit: the good news is that once you get past them just run and gun and the 35 is easy. This is the first week I have been able to take part in the 35 and thought it was a lil time consuming with the pilot servitor ( bullet sponge ) but over all an easy event. Keep moving as a team.