[cyberferret]

Those were innovative ejection seats, but sadly, similar style 'capsule' ejection seats failed during the ultimate test during the prototype XB-70 Valkyrie accident. [0]

In that case, the centrifugal forces generated by the aircraft going into a spin meant that the second pilot, Carl Cross, waited just a few seconds too long to initiate the ejection sequence, and his seat was unable to be retracted into the capsule for ejection, so he ended up riding the aircraft all the way to ground impact.

[0] - https://tacairnet.com/2014/10/27/crash-of-the-valkyrie/