2. "Split" means that something has hit him so hard that he can't bear it, so split is used to express such emotions, or when he receives a very bad notice or a very surprising news, everyone may also use this split expression to express his emotions at that time.
For example, you were very happy at the weekend, but the boss suddenly called you and asked you to work overtime at the weekend. You will feel cracked. At this time, you can use this cracked expression to express your emotions at that time. For example, your teacher suddenly assigned you a lot of homework, which made you feel a lot of pressure. When you receive this news, you will also feel a lot of pressure. At this time, you can also send this cracked expression.