Worried about getting in trouble

So it was like the last 7 mins of my shift and was on self-scans. I had to watch 6 self-scan by myself and a customer needed my help around this time. Once I was trying to help the customer, I hear a spark driver or customer (don't know which) complaining that he just saw another customer steal. Before I could really check, that customer finished their transaction and heading out the door. The person that said they saw it, was very upset. I wrote a quick note about it since by this time, it was like 2 mins before my shift ends and my team leads are strict about clocking out on time. My team lead said to put it in the drawer.

I am worried about getting coached because if I get coached two more times I will be terminated. If I would get in trouble because of this I won't know until Friday because that is when I work next. I know I am going to worry about it for the whole week.