Beyond Special Abilities, which you have mentioned, there is nothing in the rules about social skills in combat, so far. And, I am not sure there ever will be, as generally they work as in any other situation. So it's more a problem of GM adjudication than of rules: a band of orcs abandoning their raid due to a single argument from a silver-tongued PC is not very logical, to begin with.
Therefore, I'll give you a two-part answer: Firstly, rules details on social encounters in general which might be applicable and relevant combat rules, and secondly a helpful framework for better adjudication of social encounters.
In the Compendium (which is yet to be released in English AFAIK) there is a section on detailled rules for Social Encounters, in general. That section, among others, contains guidelines for social rolls of Persuasion, Seduction and Convincing, aiming to enforce actions:
A comparing skill check is rolled for the active party's social skill versus the passive party's corresponding willpower. The result is adjudicated as follows:
- Netto quality level (QL) 1-2: The passive party acts as desired, but either hesitantly or not to a full extent
- QL 3-4: The passive party acts as desired, to the active party's satisfaction
- QL 5-6: The passive party fulfills the desire and will fulfill extra wishes or help further on their own volition
This can be used as a rough framework for Intimidation, as well. What this tells us is that you'll have to focus more on the netto QL to reasonably adjudicate these actions. A simple pass will certainly not send someone running from the battlefield, but make them hesitate for a moment, at best.
Furthermore, be aware that the combat rules detail that as a free action you can utter a short sentence. Usefully intimidating someone or even persuading them will take longer and should therefore take at the very least one full action, probably more. Keep in mind that a combat round is just 3 seconds and think about how much useful talking you can probably do in that time mid-combat. Besides, targets will likely be very distracted and/or unwilling to listen, so a (hefty) negative modifier is in order.
Aforementioned Special Abilities by their very existence indicate that you're not supposed to be able to do much with a simple free action / single action social check in combat. Special Abilities cost points to buy and have very specific effects. Allowing simple checks to do a wide range of things, detracts from their value (to the point of absolute uselessness). There are a couple more of this type of Special Ability in the Compendium to provide additional means of using Social Skills as combat (free) actions.
Adjudicating Social Encounters: A System by The Angry GM
As I said, the main problem, imo, are not the rules, but GM adjudication. Social Skills are often awkward, in combat and outside, across many systems. In one of his blog posts, the Angry GM details a system for adjudicating Social Encounters and how to handle social skills, effectively.
The essence of it is this:
- An NPC in a Social Encounter has a number of Objections and Incentives. Objections are reasons why the NPC objects to whatever the PC is trying to achieve. Incentives are reasons why the NPC is inclined to oblige.
- Each Objection (-5 to -1) and Incentive (1 to 5) is assigned a numeric value to represent its strength
- A player stating an intent and an approach may lead to a roll on a Social Skill. Depending on the result an objection/incentive may be newly added or its numeric value modified accordingly (a success decreases an objection or increases an incentive).
- If the netto value of adding up all objectiosn and incentives is greater or equal to 0, the players succeed and the NPC cooperates.
There are more details to it, so I highly recommend reading the full articles on Help! My Players Are Talking To Things and Systematic InterACTION!.
This is usable in combat as well and leads to the useful conclusion: An orc horde out for loot and manflesh (strong objections to leaving the PCs alone) will likely not be dissuaded from attacking the party due to a single skill check. It will take longer to convince them (e.g. by making a strong case for not being worth the trouble by repeatedly intimidating them stating the party's past feats, pointing out their superior equipment, asking if not enough of their comrades have been slain, yet etc).
Long story short:
- Fully succeeding in a social encounter is supposed to require high QL according to detail/focus rules for social encounters
- Rules for combat round duration limit social skill applicability in combat
- A Social Skill success is hardly ever an instant "I Win"-Button.
- GM adjudication is key for reasonable use of social skills in combat.