It’s only six twenty in the evening... it was
Moments away now before finalizing everything as true,... he was moments away...
back, not unsure of his decisions .. this is a double negative. Not sure of his, or, unsure of his...
To be grammatically correct this should be slowly and carefully ... but you probably want to avoid two Ly words next to each other.
reality of the idea they confront ... confronted.
his colleagues will pursue to the very end,
he can see traffic beginning to build; ... could see. Remember, if it's in the past and he's already done it, it's always could, not can. Had not has etc.
Right, I'll stop pointing them out now. I've given you a few more to quickly change to give you the idea. Don't worry it will suddenly click into place (unlike me with commas!)
If you want me to stop pointing out the tenses, please say. But I know you're trying to get them right. I'm just going to read from here., so that I can enjoy the story.
Tense, I thought he was going to have a heart attack. Nicely written and very enjoyable.