To get down to something = to get something started = to start something seriously or with effort = to start to direct your effects and attention towards something.
Let's get down to business.
I've got a lot of work to do, but I can't seem to get down to it.
I must get down to booking the hotels.
To break through = to make or force a way through a barrier
She broke through the door and into the corridor.
The sun breaks through the clouds.
Many talented musicians struggle to break through to the music industry.
around-the-clock = nonstop = all day and all night without stopping
They're working around the clock to get it done.
The routine diagnostic methods have been complicated, painful or not accessible around-the-clock.
Ruskin Square Car Park in Dingwall Road has been fully modernised and can be accessed around the clock.
UK informal, C2, too extreme and not suitable, or demanding too much attention or effort, especially in an uncontrolled way. (exaggerating)
Printing the entirety of the application form may be a little over the top, so if you would like to omit this then please feel free!
I thought the decorations were way over the top.
The speech was a bit OTT.
He realised he'd gone over the top with the seating arrangements