Why didn't Harry use the Summoning Charm to retrieve the Marauders' Map in GoF?

Question

In my humble opinion, the turning point in Goblet of Fire, or maybe the whole of the Potter series, was when:

• Harry was wandering around in Hogwarts in the middle of night with the Marauder's Map
• Impostor Moody/Barty Crouch Jr searching Snape's office for Polyjuice Potion's ingredients
• Harry wondering why would Barty Crouch Sr be inside Snape's office at that time
• Snape catching Harry in the dark without warning
• Marauder's Map flying away from Harry's hand and landing on the floor
• Moody/Crouch Jr approaching and saving Harry from Snape
• Snape leaves, Moody/Crouch Jr picks up the Map and takes a look at it and leaves him stupefied (pun unintended) for a moment as he realises he was so close to becoming unmasked...

Now, the question is why didn't Harry use the Summoning Charm to get the Map from the floor? He still held his wand if I'm not mistaken; a quick and quiet "Accio" from underneath the Invisibility Cloak should have served the purpose.

Harry had not too earlier proved to be quite an expert at the Summoning Charm itself, when he summoned his Broom (which was locked up far away inside the school, so it should have needed one of the best Summoning Charms for it to break away the chains binding it) when facing the dragon for the first task.

If Harry had really used the Charm for getting the Map, then of course as the impostor Moody approached, Harry would've seen that the Map was still showing Barty Crouch, and he would have realized it was an impostor and alerted Dumbledore. This would have prevented Cedric's murder and ultimately stopped Voldemort's return, at least for the time being, as Voldemort needed Harry to complete his return to his original form. The whole series would have taken another course.

So, why didn't Harry use the Charm, which should have been in the top of his mind coming out fresh from the first task? Did he just miss using it at that particular moment, or would it not have worked from underneath the Cloak?

Answer 1

It appears Harry panicked and forgot he was a wizard.

This scene is very tense for Harry. I'll provide some quotes so we can see how it all went down.

As you said he spots Crouch on the map.

A single dot was flitting around a room in the bottom left-hand corner – Snape’s office. But the dot wasn’t labelled ‘Severus Snape’ ... it was Bartemius Crouch.

He was so caught up in the weirdness of seeing Crouch in Snape's office on the map he wasn't paying attention to where he was walking.

not thinking about what he was doing, not concentrating on anything but the peculiar behaviour of Mr Crouch, Harry’s leg suddenly sank right through the trick step Neville always forgot to jump.

He finds himself stuck in a step.

He gave an ungainly wobble, and the golden egg, still damp from the bath, slipped from under his arm – he lurched forwards to try and catch it, but too late; the egg fell down the long stair- case with a bang as loud as a bass drum on every step – the Invisibility Cloak slipped – Harry snatched at it, and the Marauder’s Map fluttered out of his hand, and slid down six stairs, where, sunk in the step to above his knee, he couldn’t reach it.

Now we see his cloak falls off, the egg rolls down the stairs loudly, and the map flies away. He is most definitely freaking out now and it gets worse.

The golden egg fell through the tapestry at the bottom of the staircase, burst open and began wailing loudly in the corridor below.

The egg is now out of site, wailing for sure attracting someone to his location.

Harry pulled out his wand and struggled to touch the Marauder’s Map, to wipe it blank, but it was too far away to reach – Pulling the Cloak back over himself Harry straightened up, listening hard, his eyes screwed up with fear ... and, almost immediately –

Thinking quickly he tries to tap the map to wipe it clean, can't reach, and suddenly hears

‘PEEVES!’

Now its potentially to late to cast Accio since Filch is right around the corner for fear he or Mrs. Norris will hear him.

He ripped back the tapestry below, and Harry saw his horri- ble pouchy face, and bulging, pale eyes staring up the dark and (to Filch) deserted staircase.

Almost immediately Filch rips open the tapestry so he is now in view of Harry and the map. Harry's hesitation both ruined and saved him. Accio-ing the map after he realized he couldn't reach it, probably would have gotten the paper seen by Filch. Luckily as it turns out fake moody comes and saves the day.

TLDR; This whole event happened in a mater of seconds in which Harry's fight or flight responses kicked in like crazy and while for us it seems clear he should have immediately summoned the map, to Harry he had other things on his mind and was not thinking straight.

Answer 2

It would have made too much noise

Until Harry Potter and the Half-Blood Prince, Harry (and virtually all the other students) did not know how to perform nonverbal spells. At best, they could whisper a spell, but they always had to say the words. They simply were not at the stage in their magical education where they could reliably perform magic without saying the words. As Snape says:

“. . . you are, I believe, complete novices in the use of nonverbal spells. What is the advantage of a nonverbal spell?”

Harry Potter and the Half-Blood Prince

Filch was nearby, only "a few steps below" Harry:

Sick with apprehension, he watched Filch drawing nearer and nearer in his old flannel dressing gown — he tried desperately to pull his trapped leg free, but it merely sank a few more inches — any second now, Filch was going to spot the map or walk right into him —

“Filch? What’s going on?”

Filch stopped a few steps below Harry and turned.

—Harry Potter and the Goblet of Fire

Harry feared that even his heartbeat was too loud (though this may be exagggeration). He would not have risked saying an incantation, even quietly.

Harry gritted his teeth, convinced his loudly thumping heart would give him away at any second. . . .

—Harry Potter and the Goblet of Fire

If he had so much as whispered the incantation, there would have been a very good chance that Filch would have heard, and then he would have known Harry was there. Even before Filch was standing right next to him, Harry presumably didn't think he could whisper the spell quietly enough to avoid detection.