Re: running down a crowded hall waving his weapon?
I would look at the character's STR versus the STR of the people he was trying to push out of the way. I would say his STR would have to equal or exceed their STR before he could even contemplate pushing his opponents out of the way. You could give a bonus for him using a shield (to push the others and restrict their ability to brace and fight back) and for the members of his party pushing from behind, but that would be up to you. I would also impose restrictions based on the number of enemies he had to push through.
Also, I would allow the people he pushed past, on their actions, to attack him from behind because he pushed past them without protecting himself. Unless the character had Defense Maneuver, I would give his opponents bonuses to hit him, also.