On the Abandoned Assembly level of the Ironclaw Munitions Factory, there seems to be an area of floor which deals heavy damage to the player while standing on it. Specifically here: http://i.imgur.com/ErvZl.jpg
Yesterday, whilst attempting the floor solo it killed me twice. Obviously it's an area with missiles, a spike trap and a Sparky shooting at me so it's pretty dangerous anyway. I chalked it up to super carelessness. Today, it got me again. Again playing solo, I had full health and my shield up and walked cautiously out taking care to dodge everything. One hit from something I never saw took my shield down and my HP to 1 bar. Another finished the job. Perplexed that I'd had the same issue in the same spot two days running, I revived and carried on. Once I'd taken down the Sparkies and turned off the rocket launchers I wandered back down to investigate the area. Standing in the same spot, my character just dropped in a single hit from no visible attack. I can assure you it wasn't the spikes, neither was it lag, the rest of the gate played flawlessly.
Since it's happened twice now (killed me 4 times, in fact), I'd say the bug is reproducible. Could someone investigate this area because something funny's happening there?
Did you happen to go solo at the start of that level? Going solo while things are exploding can sometimes cause insta-death glitches like that.