Intermission gives people an excuse to stand near each other without committing to anything. The line moves slowly, everyone has an opinion about the first act, and a woman who turns around twice is often hoping the conversation will not die after one sentence.
The trick is not treating her reaction like a test. If she laughs at his complaint about the staging, he can ask what she would have done differently. If her answer gets sharper and more personal, he has found the version of her that does not show up in a quick hello.
Then the bell rings. A good exchange ends before it gets overworked, and he may find her beside him again after the final curtain.
That second encounter carries more weight than a forced introduction ever could. Her friend may be waiting by the doors, but she still leaves room for one final remark before the coats come back.