Saw how badly he bled (6)
I believe the answer is:
beheld
'saw' is the definition.
(beholding is a kind of seeing)
'badly he bled' is the wordplay.
'badly' indicates anagramming the letters.
'he'+'bled'='hebled'
'hebled' with letters rearranged gives 'BEHELD'.
'how' acts as a link.
(Other definitions for beheld that I've seen before include "watched" , "Laid eyes on" , "Seen" , "Saw or observed in olden times" .)