The ambush sucks. I played paintball for many years. We KNEW ambushes or hidden attacks were out there. We were ALERT, looking for them. And yet - still you would get whacked out of nowhere. The usual result was you were out, no chance to do anything. Most ambushes are like that. If you get surprised, you lose. Period. End of story.
That being said... If you were lucky and survived the initial attack, you had to MOVE and counterattack immediately - essentially enter and attack hard and fast with everything you had.
Now, over time we developed tactics to counter ambushes. Getting the ambusher to reveal himself (or herself) early and increase the odds of surviving the initial attack was always good. I was influenced by Audie Murphy, the most decorated US soldier in WWII, who stated in his autobiography that he would approach potential sniper positions from afar out in the open and invariably induce the sniper to get impatient and take the shot early and miss.
Another tactic we liked was to guess the most logical ambush positions (by thinking like an ambusher) and essentially flank those positions to dislodge any potential ambusher. Feigning indifference by appearing to be moving straight into the potential ambush but then veering off at the last moment can also cause the ambusher to spring a much lower percentage attack thinking their moment was slipping away.
As far as knives go... My practice with "realistic" knife attacks - ambush or no - leaves me feeling naked and vulnerable. Avoid the knife and strike hard probably would work given the experiments we tried (obviously we didn't actually strike each other hard...). That's what the Systema guys show. It seems like the ONLY thing to try against someone wielding TWO knives... But those only work if you read/see/feel the attack coming...
Good Aiki probably wouldn't hurt of course...
I digress here from the subject matter.You mention Audie Murphy, one of my childhood heroes.He was a great cowboy actor especially when he co starred with Dan Duryea .Audie's biography should be mandatory reading by everyone.He was dirt poor , joined the army,and became the highest decorated soldier ever.He made Rambo look like a big girl's blouse.Audie died in a plane crash and he is buried in Arlington Cemetery. Cheers, Joe.
Ps In Glasgow he was nick named the 24hr cowboy [a play on his Christian name Audie ie Audie/all day.Glasgow venacular say AW DAY instead of All day while jawing.