a key to cut through all layers
A key to cut through all layers in the timeline rather than having to shift click with the razor tool
To add to this, better still, if you need to do this very frequently, toggle all the layers you want to cut through and do as Stuart recommends, have a keyboard short cut (better still a mouse button mapped) as add edit (to cut).
Stuart Reid commented
CTRL-A to make sure all layers are selected, CTRL-K to cut. Take some time to learn some keyboard shortcuts and you'll really be glad you did, it will save you hours in the suite.