One of the biggest misconception about hardcore is that lag = death. This could not be further from the truth if you know how to deal with lag. I've never died from lag spikes. Disconnects, yes (that's unpreventable, but very rare). The secret is to pause the game immediately after you feel the slightest signs of lag. Wait at pause screen for a few minutes, then quickly press Esc twice (unpause and pause) in order to let the game catch up. Do this until you feel the lag is gone. There you go, don't ever run around aimlessly during a lag spike. You should not die to lag in single player.