Bombers walk through or hop over wall. One day the bomber will do what they should lol, they normally go burn them selves at the nearest flame gate, see video.
Better amend your title to include Heavy Gunners. They do it also. The video is slowed down and has dropped frames for some reason, but the battle and replay were normal. After the HG teleports to the wall grid, you can see him walk over the last two segments. cc: @Lynsey [Midoki]