Setting aside the issue of orcs and D&D treasure tables, let's instead give the example of 50 alien tribesmen attacking the PCs while they're away from the ship.
(If they're in/near the ship, it's a non-starter because the starship hull renders the tribesmen completely harmless. Minus 10 dice of damage (no minimum, remember, for this modifier) is hard to overcome with hand weapons...)
But let's assume the PCs are out gathering specimens in their open-top landrover and the aliens attack.
The PCs were expecting trouble from these tribesmen, so they're armored in cloth armor (AR=6) and well armed. The landrover is a non-military model and it's broken down for some non-combat-related reason.
The tribesmen are armored in chainmail (armor bonus +5, AR=2), armed with broadswords (2d6/19-20) and longbows (1d8/x2), the best weapons of their tech level (2).
First off, the longbows have a range increment of 30 meters (let's ignore the -1 die per range increment reduction, since that renders a bow useless beyond ~100 feet, which they aren't), and let's assume the combat begins with at 60 meters across open terrain toward the PCs. The aliens' move rate in chainmail is 6 meters, so they can either advance 6 meters and fire or 24 meters and not fire AND lose their Dex bonuses to AC.
(Let's also ignore cover for this encounter.)
Combat begins at 60 m, and the aliens advance 6 m to avoid the 2nd range increment and fire their bows. Whoosh! 50 arrows fly into the sky, each at -2 to hit and -6 damage (armor rating of the cloth armor). Five PCs, each attacked in their cloth armor, each with 14 Dexterities for simplicity's sake.
Their AC is 18, and the tribesmen are 1-level warriors, so they have +1 BAB, +2 for their own 14 Dex's, and -2 for range. One arrow in 5 hits, so the PCs take an average of 9 Stamina and maybe 1 point of Lifeblood.
The PCs have several different TL12+ weapons, including two gauss rifles, which they fire in suppressive fire mode at maximum RoF (10). The enemies have an AC of 17, -4 for suppresive fire, but the PCs went through Prior History and are ~9-level with +6 BABs. The PCs need 13's to hit up to 5 targets each, and each target will take +1d damage, or 3d12. On the average, 4 targets get hit, each taking 3d12 Stamina (knocking them out) and 1d12, the highest die, straight to Lifeblood.
The other three are armed with laser rifles and need 9's to hit for their first attacks and 14's for their second ones, so let's say three of them hit, dropping 3 more targets.
The range is now 54 meters and the aliens realize they'll never reach the humans in time, so get out their broadswords, issue an inhuman chilling battle cry, and charge 24 meters ahead (x4 run).
This time, the autofire from the gauss rifles is more effective, since the enemy has no Dex bonus, so they cut down 5 more and the laser riflemen drop 4 more. The enemy is now at 30 meters and there are 16 of them down, 34 still up.
They charge again, closing to 6 meters. They're now in Point Blank range, and the two gauss riflemen have Point Blank Shot, so this time they drop 6 aliens and the lasers drop 4 more. 26 aliens are down, 24 remain, and the PCs are hardly hurt.
But now the aliens are in range of their broadswords and suppresing fire might be dangerous, but there's a lot more badguys than goodguys, so it might be pretty safe. We'll see how those broadswords do, first.
The 24 aliens divide their attacks (just for space's sake) evenly amongst the 5 PCs, so an average of 5 attack each one. They need 15's to hit (Str bonus +2) and do 2d6+2 Stamina and 1d6 (the highest of 2) -3 Lifeblood each hit.
Each PC is hit by 1.5 aliens, so on average they take 3d6+3 Stamina and 1 or 2 points of Lifeblood. Now it's getting somewhat serious.
Setting aside ammunition (the gauss rifles should be reloading now), the gauss riflemen fire suppressing fire into the melee. With 24 aliens and 4 allies, it's a pretty good bet. 10 eligible shots means, on the average, one ally gets hit (sorry, Bob) between the two, but they'll take 3d12 Stamina and 1d12 (the highest) - 4 Lifeblood IF they're actually hit by the round (50/50 there). Bad, but not terrible.
On the other hand, 9 more aliens go down, dropping it to 15 aliens. Most aliens would have run away by now, but these aliens aren't too bright, so it continues.
3 aliens per person, each needing 15s, so 1 alien hits each person, doing 2d6+2 Stamina and again 1 or 2 Lifeblood. The Lifeblood isn't too life-threatening yet, but the Stamina's adding up. 9 from the first arrow volley plus 18 from the first broadsword attack and 9 from the second is 36 Stamina damage.
The gauss riflemen stop firing suppressive fire and go to +1d bursts. Each will get two shots (+6 BAB and +1 BAB) and drop 1.5 aliens, so three go down, and another four to laser fire. That drops the aliens to 8, and the aliens are pretty much finished. They might drop one or two PCs from Stamina damage, but they cannot kill them, and they're going down next round with one or two stragglers possibly.
The situation would have been a lot grimmer without automatic weapons, a GM that was ignoring critical hits and ammunition, and range. The same bunch of aliens at point blank range would have a much higher chance of success.
On the other hand, if the vehicle had an LMG mounted on it, with its 20-round suppressive fire hitting up to 10 targets for <DEAD> damage, it would have been different, too.
Bottom line? Stamina damage is an issue when being attacked by numerous low-powered badguys, and it'll drop you long before Lifeblood does.
Now, give the badguys TL5 or TL6 weapons, and 50 of them kill the PCs pretty much every time... SMGs firing 4/bursts for damage... dead, dead, dead...
