I'm no expert but I imagine baby CG wasn't used to being in a crowded room and between the new people and the noises was scared.
20 years ago when my nephew was about 3 months old I went out to eat at Outback with two sisters and BILs and she brought my nephew. He started crying so fortunately I eat in about 30 seconds and take him outside. Calm him down and bring him back in. Instantly starts crying again so I hand my sister a $20 to cover my food and take him back outside. He instantly stopped crying. I just sat and bounced him around while they finished eating.
Possibly, he's a bit young to notice too much around him yet. He was being fussy before we left yesterday so I sort of knew I was rolling the dice going out.