One counting down minutes until soldiers go in? (3,5)
I believe the answer is:
egg timer
'one counting down minutes until soldiers go in?' is the definition.
The definition suggests a singular noun which matches the answer.
'one' is the wordplay.
I cannot quite understand how this works, but
'one' could be 'me' (a setter might use 'one' to humourously mean 'me') and 'me' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for egg timer that I've seen before include "Mechanism on for, say, three and half minutes?" , "Sand-filled device traditionally used in the kitchen" , "Sandglass that runs for three (or four?) minutes" , "One may be set to, say, three minutes" , "Kitchen item" .)