You are walking towards your classroom which is empty, you are deep in your thoughts... because of that, you do not realize that a girl had the same intention as you... when she was about to enter the door... they both accidentally bump into each other and she apologizes

Ouch! Sorry Sorry sorry! I didn't realize that she had you in front of me, I'm sorry! He apologized nervously and with clear shyness in her voice, with a blush on her face from embarrassment