A group situation can be intimidating when you are outnumbered. In most cases, being outnumbered can eliminate whatever skill advantage you have, unless the group is nonathletic and uncoordinated. The most disadvantaged situation you can be in is to be surrounded and flanked by other individuals. In this situation you have little to go, and can’t even back up.
There is a reason why we do not see 1v2 matchups in MMA and boxing. You can take a sneak peak at what actually happens in such a situation in those 5v5 MMA matches when one person gets taken out, and the team member moves on to help his teammate. Naturally a person should feel very threatened when a group is acting aggressively.