He quietly urged other military personnel to reflect on their own positions. “They should be confident in questioning possibly immoral or illegal orders,” he said, “remembering they are responsible for their own actions, and knowing others are asking the same questions.”
“If they have doubts about their orders, they are not alone,”
By quitting he is potentially allowing the administration to fill the position with a trump approved “yes man”. I think he could do more good by keeping his position and defy/resist orders instead. I don’t blame him, though. Getting the hell out of there seems reasonable too!