You are clearly doing something wrong. You don't have to break plasma sentry, just EMP it once and take the disk from a chest, then run, use adrenaline if you need it. Biocorp robots can't open doors. Zero points in stealth? Craft stealth items. If you have at least 4 STR, you can buff it to 8 with junkyard surprise and adrenaline; should be enough to open vents.