Case II: Competence$/$diligence$...$

Student: "When I co$-$oped at Company Y my supervisor asked me to do significant corrections on a programmable logic controller $($PLC$)$ program that controls the robots on a conveyor. At that time I did not have a lot of experience with PLCs$.$ I made some changes, but was not sure whether I did things correctly. So I asked the supervisor to check it for me$,$ but he did not have time. So he said $"$it is fine, I trust you". Later on they found that I had disabled the main safety subroutine. Nothing happened but it was possible that people would have been injured from the mistake and some very expensive equipment $($worth millions$)$ could have been damaged."

Questions:

$1-$ How fast can you teach yourself?

$2-$ What should the engineer do$?$ Please elaborate.

$3-$ Can he press the boss? Such act hurt the engineer's career! Elaborate on that

$4-$ Discuss what is more important, advancement or safety?