How is Thomas Becket the tragic hero in Murder in the Cathedral?

Remember, the word tragedy originated from the Greek word
'tragos' which means a 'goat'. do you wonder now
how?

Actually, in the actual greek practice, human was made
an object of sacrifice either to appease the repective god/goddess or to seek his/her
benevolence. in the later time, with the progress of civilization, the greeks realized
the horror and heinous crime involved with this ritual. then the human was replaced by a
goat.

in this ritual, the object of sacrifice was kept at
the centre while the ritual-killers surrounded it along periphery. their spears were
pointed toward the centre where the object of sacrifice was already tied or affixed to
the 'stake'. they would sing a ritual song and gradually as the song nears to close,
they constrict the periphery and move toward the centre. thus, with the end of the song,
the spears get pierced. the object, be it human or a goat, is sacrificed. As the goat
had no crime, yet it is made an object of sacrifice, hence the origin of the word
'scapegoat'. and, hence too, is the reason of the origin of the word tragedy from
'tragos'.

remember about Macbeth in Shakespeare's play.
when Macbeth has no way out to flee or to survive, when all his enemies have surrounded
him from all sides, he utters the pang-relieving
words:

"I'm tied to the stake, I cannot
fly,

But bear like I must fight the
course."

this imagery evokes in our mind the ancient greek
practice as mentioned above.

Now, consider the case the
Becket in Murder in the Cathedral. In Act II, in the murder episode in particular, he is
surrounded by four murderers. he has no way out to escape. Eliot very adroitly sketches
this imagery by alluding to the ancient greek practice of ritual killing. from this
angle, obviously, Becket is a tragic hero, a classical tragic
hero.

but there are also other points one may elaborate in
details that correspond to the question whether Becket is a tragic hero. Let's have a
look:

First, Becket is pre-ordained by God to be a Martyr.
in this respect, he is 'a chosen seed of God'. To God, of course, he is an object of
Martyr. but, as per God's design, Becket must not be aware of this. Neither Becket
should want it. because christian martyrdom is only the design of God. but in his
encounter with the Fourth Tempter, the reality of his heart's intention was revealed. he
had thought of being a martyr perhaps in the remotest corner of his mind. once the
fourth tempter is gone, becket realises his sin. if  this is his hamartia then he must
undergo the way of salvation that might bring him a redemption. and so does he. his
redemption comes through his realization of his own remark that he made in Act
II:

"Action is suffering and suffering
action..."

Secondly, Becket had to die almost for no crime
on his part. being loyal to the church or truthful to the religion can never be a crime.
yet becket suffers in the hand of the murderers.

Thirdly,
we should raise a debate with supporting arguments from various critics, whether, Becket
is really a tragic hero or a religion's martyr or both? Literally, becket is a tragic
hero. but eliot also projects him as a martyr. And as is the case, a religious martyr is
always a sufferer, so becket must be a tragic hero too. symbolically, becket is a
christ-figure, a saviour of mankind. as christ was murdered first, made a tragic hero
and then a prophet, so in case of becket, he was murdered first, made a tragic hero, and
then a saint.