Allan McDonald is a new name for me. Thanks for posting this. See also other engineers who objected to the launch, like Bob Ebeling [0], who suffered with overwhelming guilt nearly until his death in 2016, and Roger Boisjoly [1], who never worked again as an engineer after Challenger.
[0] https://archive.ph/kGMYG
[1] https://en.m.wikipedia.org/wiki/Roger_Boisjoly