Engineers VS Fortifications

[Imp]

Only stating what I see to be honest had no idea engineers got an assault bonus at all but from when I first start attacking a bunker with a view to killing it barring outside interference I would expect it to be dead in 2 turns. On occasion 1 will be very resiliant but some fall straight off to. Using regular troops it can drag on but engineers have no problems dispatching reasonably quickly. The hard bits getting them there in the first place & keeping them in good order for a solid attack
No they dont route often but if its being problomatic you can force the issue & because you are adjacent so probably have cut off its escape route it often just surrenders.

If you just attack a bunker with one unit each turn & no support it gets to attempt recovery between each attack so any suppresion could well be mild. If you hit it hard on the first turn or even before going for the kill one attack will probably keep it heavily suppressed.
Applies to any attack hit a unit hard enough that its heavily suppressed & all you need to do after is take a shot at it after to keep it that way.