Quietly leaves with order to remove underwear? (5,3)

'quietly leaves' is the definition.
Although both the answer and definition are verbs in their -s form, I cannot understand how one could define the other.

'order to remove underwear?' is the wordplay.
I cannot quite see how this works, but
'order' could be 'o' (abbreviation e.g. in British honours OM, OBE etc.) and 'o' is located in the answer.
'underwear?' could be 'slip' (I've seen this before) and 'slip' is found in the answer.
This explanation may well be incorrect...

'with' acts as a link.

Can you help me to learn more?