Long and short bursts continued to alternate, and one of MG4's bullet chains quickly emptied, Qi Lin dropped the machine gun, picked up the HK416C and began to charge forward, and at this time, No. 3 and No. 4 had already rushed downstairs to Burger King, and a grenade with a pull ring was directly thrown onto the platform on the roof.

"Boom!!"

A violent explosion rang out, and a large amount of lime powder and debris fell in a torrent, and No. 3 and No. 4 rushed into the antechamber of Burger King, raised their guns, and fired at the ceiling.

The bullets drilled hundreds of dense bullet holes in the ceiling, and their strafing almost completely blocked the route that the people on the roof wanted to leave with the stairs, and if the other party directly chose to jump out, it was very likely to hit Qi Lin who rushed over.

"I'll rush to deal with him!" As he spoke, Number Four ran to the back of the Burger King's kitchen, intending to rush up the stairs to the roof, but before he could reach the entrance of the kitchen, he was pulled by Number Three.

"Tripping thunder."

Number Three said, and Number Four noticed that at the entrance to the kitchen, there was a thin transparent line, which was normally very inconspicuous and could not be seen at all without looking closely, but the explosion just now shook a large amount of lime off the ceiling, and the thin line was stained with a small amount of gray-white powder.

"Didn't you say you're good at mine demolition? Can't find any of these obvious pitfalls? Number Three said with some dissatisfaction.

"I'm sorry, but I'm in a hurry...... Four, a little ashamed, as he retrieved a set of tools from his backpack to defuse mines.

"I'll cover for you, you tear down the trap." Three held MK5 in both hands and aimed at the staircase through the door frame, while Number Four crouched down in the doorway.

"It's a chain trap, if we choose to cross the first tripwire directly, there will be a second tripwire after a meter, and the second tripwire is glued to the ground, whether you step on it or trip it, the trap will be triggered." Four said after observing for a moment.

Although the traps were cleverly arranged, both traps were the simplest, using the pull from the tripwire to detonate the grenade hanging from the back door, and Four put his finger inside the safety pin of the grenade to hold it down, and then cut the two tripwires with a dagger with two clicks.

"Alright. The trap is lifted, let's go—"

"Stand there and don't move!" Just as No. 3 and No. 4 were about to move on, Qi Lin had already come behind them and shouted to stop them.

"What's wrong? Is there a third trap? "No. 3 and No. 4 immediately froze in place, motionless.

"See that dangling cable in the corner of the kitchen?" Qi Lin said.

No. 3 and No. 4 immediately followed his fingers, only to see that in the corner of the kitchen, the door of the electrical box was smashed, and a cable with a thickness of two or three centimeters was torn off and fell to the ground, and some small electric sparks continued to emerge from the broken part of the cable.

"I don't know why there are high-voltage cables in a Burger King's kitchen electrical box, and I don't know why the buildings in the ruins of the city are still powered, but if you take a few steps further, no one can save you." Qi Lin said solemnly.

"It's a step voltage......" As soon as Qi Lin said this, No. 4, as an architect, instantly understood, and immediately broke out in a cold sweat.

The so-called step voltage means that when a wire is directly in contact with the ground, the current passing through the wire will spread from the contact point between the wire and the ground to the ground, and a potential division area will be formed with this contact point as the center.

Within this potential subregion, the closer to the contact point, the more concentrated the current, the higher the potential, and the farther away from the contact, the more dispersed the current and the lower the potential.

There is a detailed explanation of these contents in high school physics textbooks - inside the power supply, the current will flow from the low potential to the high potential, which is the direction of the electromotive force, and outside the power supply, the current will flow from the high potential to the low potential, which is the direction of voltage.

If someone enters this area at this time, when the stride between the feet is too large, there will be a significant potential difference between the landing points of the feet, and due to this potential difference, the human body will form a closed circuit with the ground - the current flows from one leg of the person into the body and then out of the other leg......

Although this circuit may seem to have no current passing through important organs, it can cause electrocution and paralysis of the legs, and the whole person will lose their balance and fall to the ground, at that time, the current will pass through more than just the legs.

"Triple traps, the other party is also cunning enough...... "Most people will relax their vigilance after discovering the first two traps, and an inconspicuous cable may be directly ignored.

The trap created by the step voltage is very secretive, but once it is discovered, the solution is very simple - as long as the legs are brought together or the body is supported with one foot, so that the potential difference between the contact point between the body and the ground is not too large, the current will not pass through the human body.

The position of the cable touching the ground is six or seven meters away from the staircase, at this distance, it is relatively safe to jump on one foot, if it is closer to the staircase, I am afraid that only the tip of the foot will not cause an electric shock - of course, the other party will not do this, because this road is also one of the sniper's retreat routes, and no one will be stupid enough to directly block their retreat route.

The trio quickly rushed to the rooftop, but by this time, the roof was already empty, except for an abandoned M82A1 anti-materiel sniper rifle and a camouflage cloak that had been blown up by a frag grenade.

"He should be hurt."

Qi Lin glanced at the mottled blood stains on the ground that had not yet coagulated, and the blood stains extended to the edge of the roof, apparently, the other party jumped from here while they were passing through the back kitchen.

"The scale of the ruined city is not large, calculate the time, and the support from the other side should also arrive." Qi Lin and the three of them clinged to the edge of the rooftop, and except for the tallest few floors of the building at three o'clock, this position was in a near-perfect shooting blind spot.

"So what are we going to do?" Four asked.

"We have to get out of here, they can't beat us in this position, but we can't beat them either......"

Before Qi Lin could finish speaking, a black and round object was suddenly thrown from the downstairs to the roof of the building—just a few minutes earlier, they had used the same method to injure the sniper hiding on the roof of the Burger King building.

No. 3 subconsciously picked up the grenade and threw it out vigorously, and at the same time, a gunshot rang out not far away, and No. 3, who had leaned out half of his body, fell in response!