When throwing the unexpected at your characters, it’s important for those characters to react in a way that’s realistic to the situation. If you don’t, the reader is going to end up rolling their eyes or pause in their reading and scratch their head in wonder, which you don’t want. You want your readers to be into your story and to keep going with it. Worse, they could put the story down and never finish reading it.
If you aren’t sure if your characters’ reactions aren’t what they should be, have someone else, like a test/beta reader, read it first before publishing it to the world. Get their feedback. It’s important.
Unrealistic: A couple of your characters, let’s say to John and Kevin, are out hunting Big Foot, a.k.a. Sasquatch. They are walking through the forest at night then hear the snap of twigs. They stop and look around. Sasquatch jumps out in front of them and they start laughing.
Realistic: The same characters scream, when Sasquatch jumps out at them, and they run. (Be more creative with their terror besides screaming and running. But you get the idea.)
Unrealistic: One of your characters teleports for the first time in their life and they react as though they’ve been doing it all their life. (Trust me, that’s not a realistic reaction.)
Realistic: The same character teleports for the first time in their life and feels feint afterwards. (Here again, get creative with this.)
Overall, you want your readers to enjoy and take in the story you took so much time and care to write. You want them to experience it and feel it. So don’t ruin that experience for them by causing them to roll their eyes or put the book down.