Can I open an application from a script during runtime?

Using system you can also take advantage of open function (especially if you are using mac os/unix environment. Can be useful when you are facing permission issue.

import os

path = "/Applications/Safari.app"
os.system(f"open {path}")

Assuming that you are using Windows you would use one of the following commands like this.

subprocess.call

import subprocess
subprocess.call('C:\\myprogram.exe')

os.startfile

import os
os.startfile('C:\\myprogram.exe')