Whenever you die you have an option to be revived by a medical droid and you have 8 seconds after the revive to get to a safe position OR you can immediately respawn at the nearest medical center. Now the medical droid has a cool down time so if you die and chose to be revived and then die again theres probably a minute or so wait. The medical center revive is always instant. Then there are healers that can revive but that also has a cool down period.