Where bed is used near to collapse (8)
I believe the answer is:
undersea
'where bed is' is the definition.
(I've seen this before)
'used near to collapse' is the wordplay.
'to collapse' is an anagram indicator.
'used'+'near'='usednear'
'usednear' with letters rearranged gives 'UNDERSEA'.
(Other definitions for undersea that I've seen before include "Below marine surface" , "in salt water" , "Beneath the oceans" , "Submarine" , "Beneath the waves" .)