I have understood the mechanism for converting ion 1 (benzyl alcohol) to ion 2 (m/z = 107) but not the mechanism for the conversion of ion 2 to ion 3 (m/z = 79). 
Please elaborate the mechanism for the conversion of ion 2 -> ion 3. [![](https://i.stack.imgur.com/nTeLi.png)](https://i.stack.imgur.com/nTeLi.png)