Here is a good examination of tactics in films.
Yes, and … ?
Perhaps you could be a little bit more explicit about your point rather than cryptic mouth-noises?
Now that’s exactly the kind of situation where you wouldn’t use a testudo. 
The testudo was used against a rain of missiles, not in hand-to-hand combat. The men at the back couldn’t fight at all.
Not true. Cite?
Bullshit.
That’s what the formation was primarily for.
At least, that’s what the actual Romans who used it thought:
“The resulting shape, which is a remarkable sight, looks very like a roof, and is the surest protection against arrows, which just glance off it”
“all the men by the density of the formation are under shelter from missiles”
Unless you’re going to be surrounded, in which case the men at the back are useful.
I’m not saying it was the best thing to do, tactically (that would be not sortieing at all 
)
Not if they’re holding their shields above their heads.
There’s a description in Caesar’s Gallic War of Roman soldiers surrounded by a large number of enemies, and he says they formed a circle, and tried to gradually move back towards their camp. They reached almost to the wall of the camp before they were overwhelmed, and the standard bearer threw the eagle over wall before he was killed.
The ones at the back are supposed to be holding their shields facing the back in that situation:
If necessary, the legionaries on the sides and rear of the formation could stand sideways or backwards with shields held as the front rows, so as to protect the formation’s sides and rear; this reduced the speed and mobility of the formation, but offered consistent defensive strength against opposing infantry and excellent protection against arrows and other missile attacks.
I shared the relevant clip of the referred movie since I haven’t seen it for a while. Made no comment on your post, one way or the other.
Sometimes a cigar is just a fucking cigar.
Other than to post “Hmmmm” immediately below my post explicitly referencing that same movie.
The other one, if pulled, will have bells on.
Thats not an actual Roman who used it. Thats Plutarch, writing 150 or so years later. And if we are going by secondary sources off wiki, then Cassius Dio reports that the Parthian arrows decimated Crassus’s testudo forming legionaries at Carrahe,
Plutarch was a Roman. One of Greek birth, but a Roman nonetheless
I forgot that the Romans had switched to tanks by then…
… this is just getting ridiculous - that account specifically says that happened after the cataphract cavalry opened up the formation.
Or is your issue with the “used it” phrasing? In which case, sure, Plutarch didn’t fight in Anthony’s legions. I happily concede the point. Doesn’t change the thrust of my argument. That account was written by a contemporary of the Imperial Roman legions. I’ll believe their account over someone who thinks scutums can’t stop any javelins or arrows.
No, but by Plutrachs time they average legionary was much more heavily armoured, the lorica segmentata was in use and that had excellent protection against missile fire.
The scutum was three pieces of plywood, glued together. It wasn’t designed to take penetrating attacks.
And faced with leather, both sides. That kind of composite construction is precisely the kind of structure that’s good against penetrating attacks (compared to a solid shield). It was choppers (like the Dacian falx) that the scutum was worse at. Until they improved them with better edging.
Every first hand Roman account of facing arrowfire seems suggest that it was the body armour not the shield which provided protection from arrows.
Ammianus Marcellinus describes facing Sassanids and that the early versions of proto plate armour was very effective at stopping Roman arrows (which were heavier than Persian ones).
I don’t believe that the testudo was used in hand-to-hand combat. The formation is purely defensive, and it’s impossible to fight back and useless in that situation (as the clip from the movie showed).
If anyone is interested in reading Caesar’s book, it’s fascinating and well worthwhile.
But find a good translation. The translations available free online are pretty useless and unreadable.
The Penguin Classics translation is probably the best (Amazon Kindle edition), and it’s also available to borrow from the Internet Archive for 14 days, here or here.
It’s in fact hotly debated to what extent the legions actually adopted segmentata overall.
I’m not doubting the protection offered by any of the lorica. But citing Marcellinus on Sassanids isn’t really a “first hand Roman account of facing arrowfire”, is it now?
The testudo wasn’t unique to the Romans, by any means.
Caesar gives an example of Germans using a similar formation of locked shields, and its ineffectiveness in close combat:
Our troops attacked with such vigour when the signal was given, and the enemy also dashed forward so suddenly and swiftly, that there was no time to throw spears at them. So the men dropped their spears and fought hand to hand with their swords.
By quickly adopting their usual phalanx formation the Germans were able to withstand the sword thrusts, but many of our soldiers actually threw themselves on the wall of shields confronting them, wrenched the shields out of the enemy’s hands, and stabbed them from above. The Germans’ left was thus routed, but their right began to press our troops hard by weight of numbers. I.56
The Gauls also used it in sieges:
Eight miles away was a town of the Remi called Bibrax, which the Belgae, directly they reached it, assaulted so violently that the garrison had difficulty in holding out to the end of the day.
The Belgae have the same method of attacking a fortress as the rest of the Gauls. They begin by surrounding the whole circuit of the wall with a large number of men, and showering stones at it from all sides; when they have cleared it of defenders, they lock their shields over their heads, advance close up, and undermine it.
These tactics were easy to employ on the present occasion; for with such a large force hurling stones and javelins, no one could possibly stay on the wall. When night stopped the assault, Iccius, the governor of the town - a Roman nobleman, who was very influential with his countrymen and had been one of the envoys deputed to ask Caesar for peace - sent word that unless relieved he could not hold out longer. II.8
As for the effectiveness of shields, Caesar mentions Roman spears bouncing off the shields of the Gauls:
But the enemy, even in their desperate plight, showed such bravery that when their front ranks had fallen those immediately behind stood on their prostrate bodies to fight and when these too fell and the corpses were piled high, the survivors still kept hurling javelins as though from the top of a mound, and flung back the spears intercepted by their shields. II.27
And Gallic missiles intercepted by Roman shields:
Accordingly Galba summoned the centurions and immediately sent them to explain the new plan to the troops. They were to cease offensive action for a time, merely using their shields to intercept the enemy’s missiles. When they had had time to recover from their exertions, the signal would be given to break out of the camp; then they would have to rely on their courage to save their lives. III.5
We have accounts of it being used in h2h, at least as I read it. This is from Livy:
The body of Cretans alone was not unserviceable; and yet even these, though, in case of an attack made on them, they could to good purpose discharge their arrows against the horses or riders, where they were open to a wound, yet against the Roman shields they could do nothing, because they had neither strength sufficient to pierce through them, nor was there any part exposed at which they could aim. [13] Perceiving, therefore, that kind of weapon to be useless, they annoyed the enemy with stones, which lay in plenty in all parts of the valley: the strokes made by these on their shields, with greater noise than injury, for a short time retarded the advance of the Romans; [14] but quickly disregarding these missiles also, some, closing their shields in form of a tortoise, forced their way through the enemy in front;
Bonus description of shield-arrow effectiveness bolded for @AK84
Now, Livy isn’t the greatest source on military matters, but is a source nonetheless.
Note that that’s likely a spear phalanx, though, so the Germans might not have had the same close-in stabby weapons to deal with jumpers-on.
BUT
Having said all that, I’d just like to point out that at no point have I said the use of the formation in The Eagle was brilliant tactics or standard Roman infantry engagement doctrine. I merely offered it up as the use of a period tactic in a movie.