Hi Jovan,
I would like to know more about the history of people. If you are so kind please do tell.

it means that their time is confined (limited/restricted)

Τhis is the greek article (άρθρο) In modern greek grammar we have ten parts of speech, where six of them are inflected and four of them non inflected. The article belongs to the inflected parts of speech, meaning it can change in form according to grammatical function such as tense, number, gender etc. this is the definite article Singular Case/ Masculine/ Feminine/ Neuter nom/ ο / η / το gen / του / της/ του acc / το (ν)/ τη (ν)/ το voc / - / - / - Plural Case/ Masculine/ Feminine/ Neuter nom/ οι / οι / τα gen / των / των / των acc / τους / τις/ τα voc / - / - / - However sometimes you can see the article combined with the preposition “σε”. In this case we have the following “στον/στην/στο”, which is the prepositional article. Hope this was helpful :))

It means " sleepless depth of guilt (guilty feelings)" I dive into the sleepless depth of guilt with sealed doors. Μπουκαπορτα is literally the big door at the opening of a ship. In this case "σφραγισμενες μπουκαπορτες" gives the feeling of no escape.