Boruto led them to the place where he kept a watch. The place he kept a watch didn't focus on the address he mentioned. Instead he focused on the road in the front and kept a watch on what's moving towards which building. It was kinda ineffective but smart as opposed to being focused on target because the chances of being exposed is less and even if he gets exposed he can lie about watching others since he isn't particularly watching the target.
Konohamaru was perplexed because the Boruto he knew wasn't that smart, he was emotional, troublemaker, a bit idiotic and impulsive character who would've already entered the place and made a mess. He wasn't honestly expecting for Boruto to get to this point at least in the near future, but everything turned around today. It seems as if he's looking at Kakashi in his teens. But it wasn't in a teacher's character to be questioning and looking surprised as his student did extraordinarily well compared to his previous record. So, he's doing his best to act normal.
As they looked at the Building 'House of Cards' it was a 3 floor building from which there were barely any people moving in or out. In fact the doors were closed compared to other traders who have their doors wide open. It was obviously suspicious but no one bothered it and the reason was known upon asking one of the store workers. He said that it was only opened on weekends.
It makes sense because do work on weekends and use it for Lab on Weekdays is a near perfect cover up. They also got to know that it was setup just about 6 months ago as opposed to other places which were mostly here for a few years. Konohamaru ordered Mitsuki to surveil with snakes and Mitsuki went away and released some snakes to a nearby narrow road which people don't use often. They stealthily moved towards the building. After about 10 mins Mitsuki came back and said "There seems to be 2 ways to enter the building one from the front and one from the back. Front is guarded more than the back. We can probably assume that the back is for emergencies. There is just 1 underground basement which is mostly used for storage but all the experiments and everything happens in the 3rd floor and there are a lot of people in the 3rd floor so I didn't check it. The space is quite large and there seems to be some unrelated people working in the 1st and 2nd floors."
Konohamaru said after considering for a moment "I think two of you should be posted far apart in the back and me and one of you will go in from the front with me and quickly reach 3rd floor and try to capture them. If anyone tries to escape one of you two should block them till I come. Any other thoughts?"
Boruto then asked for the kid who was smuggled inside. Mitsuki said that he's found him in the second floor still in the cart. Boruto concluded that the cart was still closed because the people on 1st and 2nd floor were normal people. So, he concluded that the cart wont be opened till it goes inside the 3rd floor and said "I'll get into the cart and after getting into the 3rd floor and when they open the cart I'll bomb them immediately then you guys can just barge inside from all sides in the chaos. The 1st and 2nd floor guys I think will be vacated by the time the cart goes into 3rd because accidents are bound to happen. What do you think?"
Sarada didn't really agree as she said "It's too risky. We don't even know how powerful they are". Boruto replied with "I don't think they'll be too powerful because there was an incident where the experimented man got out and was killed outside. Even if they beef up security after that I don't think it'll be that much".
Konohamaru said with a thoughtful look "I think the plan Boruto suggested has merits but if one of you guys need to go in it should be Mitsuki because he's the most agile out of you all. Besides that everything else sounds good".
Boruto said in a rush "I said I'll go because I can use clones and confuse them and since you'll be attacking from outside they'll be confused more if they see clones."
Kon: "Makes sense. Fine we'll go with the plan. Boruto and Mitsuki go and stealthily get to the cart and replace that kid with Boruto. Then let's keep a watch in our positions. Once Mitsuki notices that the cart moved to 3rd floor we'll start attack 1 minute after that. Got it". All of them said "Yes" in unison.
Mitsuki then guided Boruto without people noticing and finally found the cart. Then he picked the lock and got the kid out and signaled Mitsuki to catch and threw the kid. Boruto then went into the cart and closed the door. Mitsuki locked it again and escorted the kid back. Sarada helped the kid calm down and told him forget everything and go back. Then they went to their respective positions and waited for an hour.
Then quietly everyone from 1st and 2nd floor started vacating the place. After a few mins everyone left and only people involved with the lab remained on the 3rd floor with minimal security in the other floors.
One guy came from the 3rd floor to take the cart to the lab.
Boruto's perspective:
As Boruto was getting bored. The cart started moving and was pushed/pulled to the top floor. Then I started preparing to throw a bomb and make some clones. Only one tiny problem remained 'How am I gonna get a Bomb now?'
While I was wondering what to do without a bomb, I heard the sound of engine whirring very near to me. I got a bad premonition and broke the cart immediately. The cart I am in was inside a Glass kinda thing and directly in front of me was something like a reactor which is charging to shoot which had a shooting nozzle of about 6 feet aiming for me.
A humble looking gentleman from the side said looking at me "Caught ya".