Coach:

"What, what?!" as he aims his gun to from whatever you freaked or jumped away from, his heart already having been going faster than should but now its running a marathon.

As you tell him what surprised you he gives you a look, as if to tell you to learn to stay calm before his heart explodes. He hates it, is a jumpscare to his heart each time. He won't die of a zombie at this point but you jerking his heart into overdrive each time.

Rochelle:

She got so tired of it she began making you do meditations in safe rooms, searches for stress balls every building you all enter, and makes you do breathing exercises.

All in hopes that you'll stop terrifying her as with you like this it makes the already shitty situation just ten times worse. She also taught you to yelp 'fake' or 'real' during your frantic fright so she knows if she should take it serious or just sigh it off.

Ellis:

Your shout or jump makes him shout or jump as well then ask in an almost whiny tone 'why?!' before laughing as now embarrassment seeps in. He makes many jokes about it, usually reenacting how you got spooked.

To make it you gotta have a sense of humor so can both laugh it off, though that is for an hour after it happened as first both have to go lower and truly sneak about as the sounds you made would have most likely attracted a bunch of zombies. Which he never blames you for as everything now is terrifying so to get spooked every corner is expected.

Nick:

The grip on his weapon tightens, every bit in his bone tightening, his narrowed gaze of focus turning to a glare of annoyance and 'I swear if that attracted zombies you'll be regretting it for the next seven years'. Sometimes he says a 'stop' through gritted teeth to avoid shouting it and attract even more potential zombies. His first task now is: both get away from this spot as he's sure you caused enough noise to attract something.

When you have big reactions to getting surprised he might sometimes roll his eyes and/or say 'stop being so dramatic' as he feels second hand embarrassment.