Yeah. that is completely acceptable. Everybody handles trauma differently. Some like to burry themselves in work because they can hide from it and as you said “be someone else” for the time being. And, some like to isolate themselves and handle it in their own way.
The only problem would be if the character was to go through trauma and then the next day the author has them acting like nothing happened at (using trauma as a plot for drama - mishandling the topic)