go into (one's) shell(redirected from went into their shells)
go into (one's) shell
1. To retreat into one's mind or otherwise isolate oneself so as to avoid undesirable thoughts, situations, or interactions with people. After getting mugged I went into my shell and didn't speak to anyone for nearly a week. I'm not good around large groups of people; I usually just go into my shell and wait until I can be alone. Don't go into your shell because you don't want an argument—talk to me and let's discuss the problem!
2. To act in a reserved and/or defensive manner. The team went into their shells after half time, trying to protect a slim lead. The senator went into his shell when reporters tried to question him about allegations of tax fraud.
See also: shell