Theory:

GERRARD: That is extremely interesting, but you seem to miss the point of my remark. I said, you were luckier than most melodramatic villains. It was not a tribute to your intelligence. You won’t kill me for a very good reason.
 
INTRUDER: So that’s what you think.
 
GERRARD: You’ll let me go, and thank God you didn’t shoot sooner.
 
INTRUDER: Come on. What’s on your mind! Better be quick. This conversation bores me.
 
GERRARD: Your idea is to elude the police by killing me and taking on my identity?
 
INTRUDER: Yes, I like the idea.
 
GERRARD: But are you sure it’s going to help you?
 
INTRUDER: Now listen here. I’ve got this all planned. I did a job in town. Things went wrong and I killed a cop. Since then I’ve done nothing but dodge.
Explanation:
 
According to Gerrard, the intruder didn't understand Gerrard's remark that "the intruder was lucky compared to other melodramatic villains." He went on to say that he wasn't complimenting the intruder's intelligence but meant to say that he (the intruder) would not kill him as there is no good reason to do so. Gerrard was certain that even if he died, the intruder's problem would not be solved.
 
The intruder told Gerrard that his intention was incorrect, which meant that he was certain to murder Gerrard since he believed that was the only way for him to survive. Despite this, Gerrard maintained his optimism and informed the intruder that he would leave Gerrard alive and would even thank God for not killing him. Gerrard seemed to have planned to deceive the intruder in order to distract him. This must have aroused the intruder's interest, for he soon urged Gerrard to reveal the reason behind the latter's statement. Nevertheless, the intruder pretended to be calm and uninterested, telling Gerrard that their talk was boring him. He also urged Gerrard to disclose what was on his mind, indicating his desire to know what Gerrard was saying.
 
Gerrard began to ask questions since he wanted to be sure about a few things. He confirmed with the intruder once again that his objective was to kill him and flee the cops using his (Gerrard's) name, and the intruder affirmed the idea.
 
Gerrard questioned the intruder once more, this time asking whether he was certain that this plan would help him elude the cops. When the intruder heard Gerrard's inquiry, he revealed the truth of how he became a killer. The intruder said that he plotted everything.
 
In the past, the intruder had committed a crime in a town. Something went bad, and he killed a cop. He's been on the run since that day, attempting to elude the cops.
 
Meaning of difficult words:
 
S.No
Words
Meaning
1.
Elude To not be caught by anyone
Reference:
National Council of Educational Research and Training (2006). Beehive. If I Were You - Doughlas James (pp. 138-144). Published at the Publication Division by the Secretary, National Council of Educational Research and Training, Sri Aurobindo Marg, New Delhi.