Two things.
1) What is the point and objective of this gamemode?
I'm not sure if its different in TF2, but in CSS Jailbreak is basically where Counter-Terrorist have weapons, Terrorist get only knives.
CT's (counter terrorist) have a "leader" that give the Terrorists commands to keep them in order, for example "crouch to the center of the map".
Counter-terrorist cannot shoot the Terrorist unless they either A) try to kill a CT, if they follow the given command wrong, or if they "rebel" by ignoring the counter-terrorist's orders or disobeying them.
Counter-terrorists keep giving commands to dwindle down the numbers of the Terrorists (dwindle down their numbers by subjecting them to various 'games' and commands that allow them to kill the ones who the command wrong or lose the 'games' they have to play) while the Terrorists try to sneak off and kill Counter-Terrorist by either sneaking up on them with their melee weapon or by finding dropped / hidden weapons / going to the counter-terrorist's weapon armory to use against CT's.
One team loses when the entire team is dead.
That's what it was like on the Jailbreak server I played on in CSS, I'm assuming the concept is mostly the same in TF2, just with Red and Blue instead of CT's and T's
It sounds horribly unbalanced, but the side without weapons significantly outnumbers the team with weapons.
In the end it's usually fairly balanced
Again I don't know if TF2 jailbreak is the same, I'm just applying the CS jailbreak concept that I've played