Maybe this will help, as it has begun helping me...
<paraphrasing> "You just worry about your own Aikido; let your partner worry about theirs." How to do that yet still be "connected" with your partners is still something I am wrestling with, but I like the sentiment it embodies.
Now of course if your partner is about to cripple you, additional tactics might be required to keep you (and others) safe, but I still like this sentiment. They say you awaken to enlightenment, it is not something you achieve, and though it is rather muddled in my own mind right now, the practice of Aikido is an exercise in realising that enlightement.
Reviewing what your Sensei said, he might have been saying the same type of thing.
Best,
-Nick