Adding emotion to action scenes isn't an either/or situation. It's just as vital to add emotional layers to the physical action as it is to have brief moments of introspection when the fight isn't going on.
Your band of adventurers may not sit around "sharing their feelings" in touchie-feelie moments like a Dr. Phil show, but they've been around each other enough to know that one hates the bad guys because they murdered his wife and children, and he's liable to attack without thought and ruin their surprise attack.
He may be clutching the sword at his side, his other hand opening and closing in nervous energy, and another adventurer may warn him to relax and may mention the wife and kids.
The image of his wife's raped and brutalized body could flash through his mind, and he fights his raw anger and lust to kill. That won't slow the action down like having a long interior flashback of him finding his family's bodies, and his vow of revenge. Instead, it adds to the excitement of the coming action because the reader now questions whether this guy will lose his cool and get everyone killed.
After some rewriting, if you still aren't happy with the emotional content of your story, you may want to look at the central story idea. Do your characters have a real emotional reason to be doing what they are doing?
Their hunt for the lost treasure should be as much about their emotional reason for needing the treasure as it is about simple greed. That emotional reason should be important enough to make the reader want them to succeed as much as they do.
Maybe the main character is after a magical sword in the treasure which is the only weapon able to kill the dragon currently ravaging his homeland, and he doesn't really care about the treasure and the life of drunken decadence and dancing girls it promises the other characters.
Maybe the other characters have laughed at him, but they've admired him and gradually they have been drawn into his quest for the sword, and in the end, they'll choose to get the sword with him and lose the other treasure.
Maybe the one that laughed the hardest and made the main character's life hell along the journey will be the one to sacrifice himself so that the hero can rescue a homeland the scoffer has never had, but now wishes to have with his whole heart.
I always use the Ben Bova character/plot questions when I'm creating a plot so that the emotional investment of my characters is always present in the action. I discuss this method in my article on using index cards to plot a novel if you'd like to learn more. You'll find it at my website,