Theory:

(The strong room at a bank, with many boxes and crates in it. Holmes, Watson, Jones and a policeman are on stage hiding behind some boxes.)

Holmes: Is everything ready upstairs, Mr. Jones?

Jones: My men are waiting at the front door of the bank and near the shop.

Holmes: Good. Now we must be quiet and wait.
(He puts out the light. The strong room is dark, but we can see the men waiting behind the crates. Nothing happens. Watson looks at his watch.)
 
Watson: (whispering) It’s 11.15, Holmes. When _____

Holmes: Sshh! Don’t spoil our investigation.
(They see a light coming through the stone floor. Suddenly the stones give way. First a hand with a gun comes out of the ground, then another hand; Spaulding comes out followed by Ross.)
 
Spaulding: (to Ross) Now, have you got________?
(With his light, Holmes comes out from behind his box, and hits Spaulding’s arm. Now the gun is on the ground. Ross quickly gets back into the tunnel. Jones wants to stop him, but he cannot.)
 
Holmes: You can’t get away, John Clay!

Spaulding: No. But Ross! My friend__________

Holmes: There are three men waiting for him at the other end.

Spaulding: You think of everything, Mr. Holmes. You’re very clever.

Holmes: So are you, John Clay! Your Red-Headed League was clever!
Explanation:
 
Holmes, Watson along with Jones, a detective from Scotland Yard and a policeman are covering themselves behind some boxes in the strong room at a bank. Holmes asked Mr. Jones if everything was ready upstairs near the other opening. Since Mr. Jones was a police, he had few of his assistants to help him.
 
Jones said that his men are waiting at the front door of the bank and some of them near Wilson's shop. Holmes appreciated Jones and said they must be calm and to wait for some time. He puts out the light so that no one can see them. The room was dark, but we could see the men idling behind the boxes. Nothing occurs. Watson looked at his watch and whispered to Holmes that it was \(11.15\) P.M. Holmes asked Watson to keep quiet as it will spoil their search.
 
After some time they see the light emanating through the stone floor. Suddenly the stones give access. First, a hand with a gun appears out of the ground, then the other hand. Holmes notices that it was Spaulding whom he saw in Wilson's shop. Spaulding comes out of the stone floor followed by his accomplice Duncan Ross, the head of the league.
 
Spaulding tells Ross if he as got it now what the situation was. Ross and Spaulding dug a tunnel from Wilson's shop to the bank's locker room as the bank was right behind Wilson's shop. Holmes appears out from behind his box and hits Spaulding’s arm as he is holding the gun. Spaulding's drops the gun on the ground. By seeing the Holmes, Ross instantly gets back into the tunnel to escape from the place. Jones desires to stop him, but he could not as Ross is inside the tunnel. Holmes says that John Clay/Ross can not run away.
 
Spaulding said his friend could make a getaway. Holmes assures Spaulding that his accomplice will be caught soon as there are three men of Jones are waiting at the other end of the tunnel near Wilson's shop. Spaulding was astonished and said that Mr. Holmes thinks of everything, and he is quick. Holmes responded saying that even John Clay was intelligent and his Red-Headed League was smart.
 
Meanings of difficult words:
  
Numbers
Word
Meanings
1.
Crates Packing case.
2.
InvestigationSearch.
3.
TunnelUnderpass.
4.
CleverSmart.
Reference:
State Council of Educational Research and Training (2019). Term-1 English Standard-7. The Red-Headed League by Sir Arthur Conan Doyle (pp. 45-49). Published by the Tamil Nadu Textbook and Educational Services Corporation.