Starts to enter the chamber, it's obvious what comes next (3)
I believe the answer is:
etc
'obvious what comes next' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'starts to enter the chamber' is the wordplay.
'starts to' indicates taking the first letters.
The first letters of 'enter the chamber' is 'ETC'.
'it's' acts as a link.
Can you help me to learn more?
(Other definitions for etc that I've seen before include "And so on, briefly" , "Etcetera (abbrev.)" , "And so forth (abbr)" , "'And the rest, in short (3)'" , "And so on, in brief" .)