Every base in market has several hiding places, some more common than others. Thankfully most of them are easily cleared with a grenade, although if you don't know precisely where someone is it can take some time to flush them.
Arnhem
Arnhem can be a beast to capture and control. Being the center base doesn't particularly help the fact that there are several places where a single guy can hold up the works for an indefinite period of time, especially if nobody knows how to deal with him.
Thankfully all of arnhem's hiding spots are accessible via grenade, it's just a matter of knowing where to look.
Few people seem content to stand around in the middle of the base near the flag. Your standard fucko will make for one of the two rubble buildings.
This ruined building is a favorite hiding spot. I use it myself on occasion. There are three ways in. Obviously, the door on the right and the window type gap on the left, but it's possible to jump in from the crack in the alley on the left, where the crates are. This requires some precise timing and with lag can be a bit difficult, but it is possible.
As far as exiting this rubble, you can go out the front doors, duck down into the alley with the crate from that crack in the wall, or leap out the back windows (provided you have the health to spare).
Another ruined building provides another hiding spot. Three ways in, the door on the right, the window on the left, and the mostly dirt filled gap to the left of the door. You'll have to go prone to slip in, but it's possible. Exits from this building include the entrances, but you can also jump out the back windows and land, in radius, on the Stone Bridge side of Arnhem.
Since I just mentioned it, you can hug the wall on this side of arnhem and be in flag radius the entire time, while also stocking up on ammo at the convieniently placed ammo crate.
This area is also in flag radius, so long as you hug the walls on the right, although you're open to fire from anyone advancing from the church.
This ruined building is another favorite hiding spot. In this picture, anything to the right of the broken staircase is in radius. The crosshair mark in the corner is a favorite hiding place, as is this window, where people can be prone and open fire on the outside.
While storming inside is the simplest method of clearing the building of anyone, you can throw a grenadeat this window and probably clear the place out, although for better odds you should jump and throw a slightly charged grenade in, which will roll in the windowsill and would kill anyone hiding there and probably severely damage anyone in the other corner, if it doesn't kill them outright.
Another popular hiding place is this three story building. The entire thing is in radius, but most people tend to hide on the third floor, prone facing the staircase at about where the crosshair is.
Keep in mind that they could be anywhere, it's simply my experience that most people, when chosing this building, hide there.
Moving right along, the final points of interest for Arnhem are the rooftops. A lot of people enjoy flying directly to arnhem and bailing out up top, supposedly safe from harm.
Remember, they can land and be in radius on any of the buildings of arnhem, but generally people tend to prefer going prone around where the crosshair is on each of those pictures, as they tend to believe they are safer there.
Luckily, all of these areas are easily grenaded, so they aren't at all safe up there, provided you know that they're up there in the first place. Be on the lookout for empty planes appearing over Arnhem. Through either intent or accident, more often than not a former pilot winds up on one of these rooftops.
If you're having trouble grenading it, stand on the back side of the building and throw a grenade almost straight up, with a tiny, ever so slight arc in the direction of the building. It should land up top with minimal effort. If you run out of grenades, you can re-stock from the ammo crate at the back side of rooftop 2.
If they're on rooftop 2 you can just spam grenades from the crate area until you get them, but it really shouldn't take more than one, once you get it down.
Arnhem Bridge
While not nearly as problematic as Arnhem itself, the bridge does have several areas where someone can gum up the works, including everyone's favorite homo hole, the three story building.
People seem to really love to hide in here. Thankfully it's not too difficult to deal with them, even the more pesky sort.
If they're in the second or third story, you don't have to go inside. Just throw a grenade here for the third story and here for the second story.
Thanks to the layout of the second story, you may need two or three grenades to clear it. Thankfully there's an ammo crate at the base of the building so you'll have no problems clearing it out. Unfortunately there are a couple of other dastardly deeds that this building is used for.
Much like Arnhem, pilots love to bail out on top of the building, and can generally be found hiding here. Make use of the ammo crate and grenade the hell out of that puppy until their body sails.
Another favorite tactic of twatwaffles across the globe is to drop exppacks at the bottom of the stairs and hide at the top of one set and wait for someone to come up. Luckily this is relatively easily countered.
Using this image as a reference, I can guide you through the process of snuffing them out. It's actually fairly simple. They'll be hiding at the peak of the halfway point, on the left, with the exppacks somewhere on the ground floor on the bottom right. You can bounce a grenade up those stairs without ever actually being visible to anyone on them. It may take one or two tries but you have three grenades and if you run out there's an ammo crate right there.
A variation of the same tactic is to put the exppacks at the peak of the halfway point, on the left, and hide at the apex of the stairs on the second story, at the top right. This is even easier to counter as a grenade thrown in the window of the second story ought to land right in their laps.
As for the rest of the base, be aware the the area underneath the bridge is mostly in radius, as is the area at the base of the hill beneath the bunker.
