A possible sign of an introvert?

Today, we had the American playgroup meet in our home. There were six kids total (including Elijah) ranging in ages from fifteen months to three and a half years old. Elijah does pretty well playing on his own or around other kids when we're at other people's homes. But, he was pretty overwhelmed by the invasion of all these kids in his room, who dumped all his toys on the floor, and got into whatever they could get their hands on. He even screamed once and yelled for mommy quite a lot. Although he is easy going, he is also pretty particular about things--such as putting things back where they came from, making sure that the cap on the markers are on, and finding any small items like dirt or whatever off his feet and giving them to me. So, I think he was upset by how his room was in "disarray" in matter of minutes after the kids arrived.

At one point, he got up from his room, walked over straight to our room, climbed onto our bed, grabbed a book on the bedside table, and began to read! Not a word about what he was doing, or calling out for mommy to come. I guess he wanted some peace and quiet and he knew where he could go to get it. All the moms were astonished by this little guy's behavior and we all had a good laugh over it. When he was done and ready to go back, he walked over to the room and reentered the mess. I guess it was his solution to the problem that he was faced with. It was just amazing to watch this twenty month old remove himself from the frustrating scene, find a way to give himself some space, and then go back to what was going on. I have no idea if this is any indicator that he is an introvert too, but I will always remember this little solution of his.