Off the bat, your unit of soldiers would not comprise of extremely different weapons. From the exact timestamp you linked, 1:14:29, you can see (I have no idea about the nations that are represented here, so I'll call them blue and red) that Team Blue has what appears to be an amalgamation of swords, halberds, and spears, with the same rough setup applied to Team Red. A formation that would not work at all in the medieval scene (unless you theorised some elaborate formation that would probably be thwarted amidst the heat of the battle anyway), due primarily to how different the weapons were and their associated styles.

In terms of formations, for the most part, your unit would approach another as a generally uniformly straight line, or at the very least uniform - you didn't have one or two people moving faster than the rest, as you can see at the very start which happens from Team Blue. Team Red does maintain their line for a small period of time, however not for long. At around 1:14:33 or so, you see a lone member from Team Red charge forward to engage the Team Blue side. I don't know exactly what he's thinking, but it's definitely not a good move - you have no backup from your fellow soldiers, and you're running into at the very least two enemies (if not more). This breaks the otherwise beautifully formed unbroken defensive line that was Team Red, and within 3 seconds you see about 4 people converge on the lone Red soldier. Whilst the person from the second rank of Red's unit could step forward to take his place, it's essentially a wasted death. Not good. To further emphasise this point, at 1:14:41, you see even more people pile on to him - he's surrounded by several Blue soldiers, and none of his own. By this point, he's either dead or regretting his choice to charge forward, and the only real option for survival is to attempt to run. And then, the larger-framed shot at 1:14:46 - there's this one Red soldier by himself, a good 3 or 4 metres away from any other source of help, taking on 3 people (and, of course, losing).

To answer your first question, on people getting hurt wearing these armours, for the most part no. That's what armour was essentially designed for, to not be hurt by their contemporary enemy's weapons. There are weaker points, and possibly unprotected areas that aren't covered by armour, and weapons do manage to cut through - spears can pierce armour or stab at unprotected areas, and various other weapons can be used to hack and bash at the enemy until they die. If you were injured, or tired, you could choose between continuing to fight and hope that your lead officer, or his commander, would rotate your unit out for fresh soldiers, or you could fall and essentially get trodden over by men and horses alike. To deal more directly with people getting hurt - arrows loosed could pierce your armour too, causing wounds that ranged from mere scratches to fatalities, concussions also worked if you bashed at someone hard enough.

Another important factor within battles is morale. If you see your friend die, like what happened to those two Red soldiers, you're psychologically worse off compared to the enemy, and your fellow soldiers may feel the same. If this continues on, or if any number of other scenarios happen, eventually one side decides to break and run for it. There's no point fighting, they're going to lose anyway, and so on, however it has happened where a routed unit flees, regroups away from the battle, and goes back in. Cavalry charges into the flanks of a unit can cause terror, further impacting morale, and cavalry can also be used to chase down fleeing enemies, harassing them far away from the battlefield so they can't regroup.

A better question perhaps would be to ask - how were medieval battles ended? They ended either with what happened above, with enemies routing and escaping, or these enemies could be surrounded by their opponents and slaughtered or enslaved, and sometimes even, the two armies would set up camp across a valley, wait a few days or weeks, and then simply decide to stop wasting their time or expending their resources and leave.