Like I said, you'd need to examine two things, one operational, one at least semi-rules based:
1. Operational: You need to really think about signs of problems that can be encountered before the problems are. Some of the PF2e Exploration Actions probably help here, but you're going to need to strongly avoid potential blind surprise situations (where its unlikely that the PCs can reasonably detect the problem before they trigger it). You also need to make it blindingly clear that they need to do those Exploration Actions and pay attention to them.
2. Semi-Rules Based: As with most editions of D&D (there are a few I don't know well enough to overgeneralize about), its not self-evident in all cases that trying to flee when things go wrong is particularly going to go well unless the only purpose of an opponent is to drive you off. When you have relatively low level creatures that can generate 40' moves and/or fly, trying to run away with a 25' move is, on the face of it, not a winner. You probably need to develop general evasion procedures beyond what the game currently has, and ones that tend to favor those fleeing. Otherwise the first time someone runs into, say, a dire boar (that's not what they're called in PF2e, but that's basically what they are) they might as well fight to the death because running away is a loser.