Thanks for that historical source document Kubarque.
A recurrent theme in U-2 and SR-71 spacesuit ejections seems to be problems with the quick disconnects, QD's, on the suit hose fittings. In some cases the flailing hoses have been known to shatter the helmet visor.
Here is an account of the first successful U-2 'ejection' (perhaps actually a bailout from the timeline) by Colonel Jack Nole on September 26, 1957:
Ejecting from the U-2 was no simple process. Each hose, tube and connector had to be individually disconnected, including the shoulder harness and radio connection. Nole had shut down the engine when he first observed the trouble. His pressure suit had inflated and further restricted movement in the cockpit. He struggled to release himself from the various connections then released the canopy and exited the aircraft. He faced another problem after he had ejected from the aircraft.
At this altitude, he had two choices. One, he could pull the cord to open his parachute and allow himself to get oxygen from his emergency tank. Two, he could free fall and risk suffocation. There was a possibility of freezing to death if he opened the parachute at such high altitude. He remembered his training—any action was better than no action, so he pulled the ripcord.
As he descended, he was swinging alternately face up then face down. For the first time in his 17 years, in the cockpit, he became violently airsick. When he landed, he came down on his seat pack on his bottom. Investigators said it would have broken his back without the pack.
As a result of Colonel Nole's incident, many changes were made in the U-2, the most significant being the ejection seat. The first U-2 was designed without ejection seats, but “the decision makers” soon decided to install one in each aircraft. Quick disconnects were also incorporated for all systems and harnesses.
Colonel Nole's successful ejection contributed to the future survival of countless other pilots.
From: Remembering the Dragon Lady: The U-2 Spy Plane: Memoirs of the Men Who Made the Legend (2012)