Of course not. Even Olympic marathon runners must pace themselves. If not, the body parts will break down. And with burnout, over time, the mental apparatus also wears out. In fact, one reason the fourth stage is so disorienting is that a person's psychological defenses have worn down.
Cracks start appearing in the defensive armor.
Painful memories and old hurts normally contained by your emotional defenses are leaking through the cracks. A slight or an emotional bump can set off an overly sensitive and personal reaction. Now a mate's occasional, somewhat annoying behavior really irritates as it reminds you of a mannerism of your father. Or jealousy towards a colleague reeks of sibling rivalry. A lot of other folks would have jumped ship much earlier.