Could you possibly be more specific? Are you referring to sub-events when you are talking about indentation? Most things are done with the mouse.
As for debugger keyboard shortcuts, unfortunately I don't know about that. I opened up the debugger and tried a few obvious choices for pause and step and things like that, but no dice.
There aren't any listed in the info page here (aside from ctrl-f5 to start the debugger):
https://www.scirra.com/manual/169/debugger