Slip away (6)
'slip away' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for escape that I've seen before include "Elude; break free" , "Way out (from difficult situation)" , "Elude; leakage" , "Get free from captivity" , "Get away from captivity" .)
(Other definitions for elapse that I've seen before include "Go past" , "'Pass by, as time (6)'" , "pass in silence" , "Passing" , "Glide by" .)