How does Hunger of Hadar behave in confined space?

Hunger of Hadar has a curious wording:

A 20-foot-radius sphere of blackness and bitter cold appears, centered on a point with range and lasting for the duration.

Compare this to Fireball:

A bright streak flashes from your pointing finger to a point you choose within range then blossoms with a low roar into an explosion of flame. […] The fire spreads around corners.

And Darkness:

Magical darkness spreads from a point you choose within range to fill a 15-foot radius sphere for the duration. The darkness spreads around corners.

Total cover rule here states:

A target with total cover can’t be targeted directly by an attack or a spell, although some spells can reach such a target by including it in an area of effect.

What would allow or require Hunger of Hadar to appear in a different shape or size?

Most simply this would be mundane walls, though I guess manufacturing a glass container of desired shape wouldn’t be hard, and then there’re spells like Force Cage and Leomund’s Tiny Hut. These would block most spells, but the HoH spell description is very explicit… a 20-foot radius sphere appears, no buts, no ifs. Is there a rule which would override the HoH description?

Spell combat in confined spaces, are there penalties?

I’ve got a Brute Vigilante who also enjoys taking an Enlarge Person potion now and then (we’ve ruled that the brute ability is not magical and can stack with the magical enlargement).

I’ve read and implemented the rules on squeezing, but that doesn’t deter him (and that’s fine), he enjoys being The Hulk.

Now, the problem arises when the spellcaster, a magus, needs to get through to join the combat and cast a spell. I’ve implemented squeezing constraints on the combat (-4 to AC, -4 to hit), which also means the Magus’ turn cannot end in the same square as the Brute (a pain for the magus as this would make Spellstrike more effective/easier). The question then is, can the magus squeeze into a shared space (with a 5-foot step) and use spell combat?

Is close quarters combat with firearms in a confined space considered a hazardous task?

I know firing indoors has the potential to hit walls, hulls and equipment, but from the rules this is potentially an additional armor value if a player or npc has cover. I also see where some combat tasks are hazardous if untrained. What I can’t find is if firing indoors should be considered hazardous and failures (or fumbles) roll on the failure and potentially mishap tables. (Like a hull breach if it penetrates or a ricochet otherwise.)

Is this covered anywhere? I have both the original Traveller 2300 rule books (Referee’s and Players’ guides) and the 2300AD CDROM canon (which includes the Adventurers’ and Director’s guides).

Traveller 2300 was renamed to 2300AD, some changes were made and quite a few rules were expanded or added. I’m only curious about Traveller 2300 independently if rules that cover this are only in one edition or are different between the editions.