Risk in involved in achieving high altitude that can lead to altitude sickness. You need to acclimatize properly throughout the trek. Pay keen attention to your body. Do not push it beyond what it can take, at least not in areas of high altitudes that might cost you your life. Otherwise, the route is pretty much safe as it is devoid of crevasses. You could fall a victim of Yak injury. When you see one, do not panic and allow it to pass.