During the second act, he could be heard yelling, “Wow!” after a performance of “Playing Nancy,” sung by Rebecca Faulkenberry. By the time the cast was bowing on stage, Mr. Murray was in tears. He waited a minute to compose himself before joining the rest of the audience to cheer the cast.

Afterward, Mr. Murray took more pictures with fans. When Zoey Jacobs, 11, approached him on crutches, Mr. Murray told her: “Don’t sell short on the rehab. Otherwise, you’ll limp and gimp for a long time.”

Then Mr. Murray, Mr. Doyle-Murray and Mr. Rubin went backstage to greet the cast and take pictures. Mr. Murray was clearly still moved by the show, telling the conductor, David Holcenberg, “It really killed me.” To Sean Montgomery, who played the sheriff, he said: “It was really beautiful. You got me. You really got me.”

Eventually, he addressed the whole cast.

“As actors, I can’t respect enough how disciplined you are and how serving you are of the process,” Mr. Murray said. “There’s nothing worse than seeing someone that’s out for themselves. And you are all in it for each other.”

He did have some suggestions, though.

“When you ever feel you don’t know what to do, sing to the person next to you,” Mr. Murray said. “And that person will sing to the person next to that person, and then you will have this force that’s even stronger.”