AFV Leading activation questions

[Blackcloud6]

"Maybe the concept of unloading while HT provide covering fire is more Hollywood then Combat?"

Yes.  The HT is to provide protected mobility, the MG on it is more for defensive purposes or supporting by fire from range and defilade.  The HTs are an important and precious asset and since they are lightly armored, exposing them risks that asset.  That is why APC doctrine up until the advent of the IFV was to dismount in a covered and concealed position.