He did not take risk, regardless right or wrong. In the post you quotedHe made the decision to return, and it was not rejected by the air control tower. That it was approved was in part because you don't want to argue with a dead man, and that he was allowed to fly again was because the bomb didn't blow.
I think he took the wrong risk. A partially-successful detonation could have been played as a propaganda victory, and the explosion would still have confirmed that the bomb worked.
Think about it this way, choosing to blow himself up makes the explosion his own problem and the failed detonation the problem of his superiors, who can try to learn, and try again. Choosing to return to base, on the other hand, endangers the rest of the base, and could have resulted in the deaths of many involved in the Chinese nuclear program. I can't imagine this decision going well with his peers.
, it is Zhou Enlai, the Prime Minister who made the order (to return). Zhou is the commander of the program's commander. Once again, it demonstrates that it is not the pilot's position to decide, but only his offer of the best alternative for the program because he is very confident to land it safely, it is up to the highest leader to decide.It was Zhou Enlai himself who gave the order to evacuate.
Why it was a best alternative? It is best for the program (to save time) to figure out what went wrong (it turned out to be problem of the release mechanism) in short time. The next try happened only months later and was successful. If he ditched it, it would probably be years away without examine the aircraft and bomb. You know that around that time 1960s, both US and Soviet Union had threaten to nuke China. China has no time to wait, not even a day.
Regardless alternatives, the fact is that it was the top leader's decision, not his. He only did what a soldier was supposed to do, follow the order. If the order is "save the bomb", then he save the bomb, his life or other's lives (the other two on the tower) were not his concern.
In a sense, like in a battle field (same as this program being military), a general's objective is to win the battle, NOT to save anybody's live including his own. Of course he would want to keep the casualty as low as possible (because he is not to murder his men), but he should be willing to pay the cost of lives for the battle, it is his duty. Now apply that to the pilot, the program commander, the controller and the prime minister, you should see that they did what they deem to be right. It is a different mind-set from commoners. That is why one should be careful with war, military etc., no jokes there.