The mission's objective is to score 20 kills using two Beretta pistols. If you fire in short series, you do not have to worry about spraying. With longer bursts, try to pull the weapons down. The only downside is the long reload time. Below, 3 interesting spots, where you can set an ambush, have been presented.
In the above screenshot, there is a corridor to the stairs, which may be used by the opponents to get into the building. There, the area in which you can move around ends. By leaning out from behind the corner, you can find out if opponents attack from there or not. If so, you can wait for them right behind the corner and open fire. A good idea is to throw a flash bang grenade into the corridor, which will make eliminating them easier.
Right next to the respawning point, there is a cottage and an open hatch with a ladder. By using it, opponents can quickly get into the building and attack the point where the bomb has been deployed. A good habit is to check this spot occasionally, especially since at the top of the ladder there is an excellent shooting position. You can wait for the opponents as soon as you see a head, or approach the edge and fire straight down.
As you go a bit ahead from the respawning point, you can take a look over the wall and make sure that opponents are not attacking. If this is the case, you can immediately engage them, or alarm an ally and back up into safety. If after you lean out from behind the corner you spot them heading towards the stairs, back up into the spot in the corridor and prepare yourself for the attack.