In "The Pardoner's Tale", where does the old man tell the rioters to look for Death, and how do the rioters treat the old man?

While the three rioters in the Pardoner’s Tale are restlessly looking for death, they meet a poor, old man on the way.

An old man, and a poor, with them did meet

Although the old man talks to them very politely, they are very rude to him.

This ancient man full meekly them did greet,
And said thus: “Now, lords, God keep you and see!

One of the three rioters “that was most insolent of the three” even asks the old man why he was still alive.

Why do you live so long in so great age?

The old man replies to his questions politely saying that it is God’s will and that even “Death” isn’t interested in taking his life. He adds, however, that it was “no courtesy to speak to an old man despitefully”

As the old man prepares to leave, the three rioters ask him where “Death” was since he “spoke just now of that same traitor Death”. They tell him that he was a spy of death, who was involved in killing their friends.

Hear my true word, since you are his own spy,
Tell where he is or you shall rue it, aye

The old man tells the three men that if they want to find death, they have to first “turn up this crooked way” because “Death” was hiding under the oak tree over there.

Under a tree, and there he will abide;
Nor for your boasts will he a moment hide.
See you that oak? Right there you shall him find. 

He tells them that they will certainly be able to find “Death” there and it will not run away or hide from them.

Nor for your boasts will he a moment hide