In harm's way

More than 450 people have been arrested in London and more arrests are being
made this morning.

At least 70 people have already been charged in London. Other forces ?
particularly West Midlands in Birmingham have made a significant number of
arrests.

She said that extra courts and a virtual court will be used today in London to
deal with cases straight away.

She paid tribute to the 6,000 'brave men and women' who are putting themselves
in harm's way.

'We need to make sure intelligence is used properly,? she said. ?This is about
criminality, and police being able to protect the public and follow that
through. They'll be working through CCTV footage and witness statements.'

'We can bring an end to this with robust policing and the help and support of
local communities.'

..............

I have never heard the words 'in harm's way'.

Is it grammatically correct?

I looked it at in dictionaries.

You had better look at the word 'harm' in the dictionaries.

There is not a single entry about the words 'in harm's way'