There are multiple factors that determines how long a match runs.

For example, we have an arena which is 21 barrels long by 14 barrels 'tall', if you do the math, (which I did in a previous version of this post but I lost my calculations because graalians logged me out.) there is alot of barrels to clear before you get to your opponent. Due to the arena size, it would take longer to clear a path with lesser players in a match.

There is also the possibility for players to try to run away and purposely prolong the match. This type of system prevents the option of running away after a certain amount of time.

Just to note, Stefan designed the system which decided to make sure the arena functions like it does now. (Excluding the current bug)

This will be fixed by friday.