Can you please check these sentences I corrected myself on the basis of your suggestions?

1) On that particular night, unlike the preceding seven nights, the narrator opened the door with greater caution than the nights before.
2) However, he made a noise when he was going to open the lantern and the old man immediately sprang up in bed and got scared.
3) The old man’s eye was open, which made the narrator angry and froze his own blood. The narrator kept still, he didn’t move a muscle and said nothing.
4) The narrator began to hear the beating of the old man’s heart. The beating of the heart occurs, however, within the narrator himself. (It is established at the beginning of the story that the narrator is over-sensitive –that he can hear and feel things that others cannot.)
5) We all know that in moments of stress and fright our own heartbeat increases so rapidly that we feel every beat. The narrator did not just kill the old man, but he buried him in the floor of the old man’s own room.

3. run-on sentence

http://grammar.ccc.commnet.edu/grammar/runons.htm

All else is fine. Nice!

1) The sentence seems grammatically correct and conveys the intended meaning. However, to check the accuracy of the corrections you made based on the suggestions, I would need to see the original sentences and the suggestions themselves.

2) Similar to the first sentence, without the original sentences and suggestions, it's challenging to provide a comprehensive evaluation. Nevertheless, the sentence appears to be grammatically correct, and there doesn't seem to be any glaring errors.

3) Again, without the original sentences and suggestions, it's challenging to provide an accurate assessment. However, the sentence appears to be grammatically correct and conveys the intended meaning.

4) The sentence seems grammatically correct. It is explaining that the beating of the old man's heart, which the narrator hears, is actually happening within the narrator himself. It also mentions that the narrator is portrayed as oversensitive, able to hear and feel things that others cannot.

5) The sentence appears to be grammatically correct. It highlights that the narrator not only kills the old man but also proceeds to bury him in the floor of the old man's own room.