My ideas are fairly simple.
1.
A map on a bridge, with two levels. At the end points of the bridges there are barricades that if you cross you get shot. On the map there are driviable vehicles that drive straight forward and you can somewhat control with the movement stick.
2.
A map on two london double decker buses.
You would be able to jump through open doors to get to the other bus, at the risk of getting shot or hit by a car. On the top level it would be torn off, but you would have a clear shot at the enemys with the risk of being in the open. RCXD's would get across by the way you get across.
3: A mix of the rusulka and the underwater lab.
On this map you would be able to swim between the boat at the underwater.In a short cutscene people could shoot you as you put on scuba gear and jump into the water. You also could be shot as you swam to the underwater station.