I'd run that Sentinel through the paces with a digital multi-meter without any atomizers attached. I'm not familiar with the Sentinel mod but I have had a dead short in my mech. Mine turned out to be the a loose 510 positive pin in my Atty that was grounding out when I tightened everything up. Your issue sounds like it might be in the mod, or how you're attaching atomizers to it. I'd also check that the battery wrap is not damaged which can cause a short as well.
There are so few moving parts with a mech that you should be able to track down the issue. If your battery is not damaged, the issue is in the switch, 510 connection of the mod or atty, or the coil of the atty. It's happened with multiple atty's that later work on other mods, so I'd start looking at the mod's 510 connection.