Seems to me it should be "...all THE doors!"
"... all the doors" is also accepted.
In this sentence, how can I distinguish, if it is imperative or normal indicative? (We quickly close all doors) Zavřeme can be indicative and imperative, if I understand it right.
Sorry no - that report was wrong - I forgot it was let's...
You do not need to comment about an incorrect report. Most of the reports are some kind of typos. It is less work to dismiss it when the time comes than dealing with comments.
Got it - don't mean to make extra work - you all do wonders as it is!