Liens did not care about the guard's alarm, as he had intended to attack head-on from the start.
What he wanted was as many people as possible, so he could experience the death threats he felt back at the Training Camp.
Therefore, he even waited for the guard to shout a few more times before swinging his sword and slaying him.
Unlike the guards at the Training Camp, the guards stationed at the Military Fortress wore leather armor.
This might be due to the different working environments of the two.
Here, the guards needed to defend against outsiders, while at the Training Camp, they watched over Slaves. With high walls separating them, they basically didn't need to face outsiders.
And Liens and the other Slaves basically had no weapons, so naturally, there was no need to put much effort into their armor.
After all, things like leather armor and full armor, not to mention the cost, are definitely not as comfortable to wear as normal clothes.